Aerobatic jet glider???

[Doc J]

Hi Gents,
with the advent of diminishing model jet turbine engines cost and higher power, plus more reliable, more compact Jet units available its seems there is a considerable and growing interest in jet gliders in Europe recently, and I'm wondering if he same applies to the US.

Now in this case I'm not referring to the "back strapped, or hidden/retractable gas turbine engines added/attached to scale gliders - which are relatively common, but mostly dont work well for reasons many and various.

There have been a few largish models emerging lately, An EDF type from RCRCM which has just about every design fault I could think of, and few I had not seen before. Nothing to be learned there.

Then more recently the "Jeema" and "Jeemax" form Glider-It with the "Jeemax being the more recent design: https://www.glider-it.com/index.php/en/our-glider-models/the-glider-model-jeemax#blockrandom

I think that if you took a step back and looked at the "Jeemax" from the point of view of its design and performance objectives then there might again be a few errors. Problem is that it does not appear to actually have any performance objectives, or if it has then its unlikely to be able to meet them.

According to my ideas, a jet glider shouldnt be just that. I.e: A model aeroplane that flies a bit faster than a "conventional" glider with the "Gimmick" of a a nice hissing/roaring noise. There should be more.

A jet glider from the flyers point of view should be (At least)

• Light, strong, practical.
• Very easy to fly under all conditions
• Highly aerobatic with Vectored thrust.
• Able to take off/land under its own power.
• Very high power to weight ratio 3.0 M span, T70 type engine (7 Kg thrust) with an AUW of under 4kg.
• Good looking and efficient
• Easy/safe to use
• Highly aerobatic (Vectored thust)

Has anyone any more suggestions here?

I am looking at this quite seriously - On the surface of it, its not a hard charter.

I look forward to your thoughts.

Cheers,

Doc

 

[Wayne]

I have no experience with this, but I have seen a few massive turbines that 3D. Pretty impressive shows. They look very jet like and appear to weigh almost nothing. They have thrust vectoring. They can do things you would not think a turbine could do. (I suspect they may be altering the thrust cone to get accerration when needed?)

I have noticed a small trend of turbine gliders similar to the Jeemax. For the most part these seem to be off shoots of the full glider versions of the models. They typically share the wing and tail with something else the company is already making. The performance of the Jeemax does not seem very impressive considering what has been invested into the model. She is a big girl though, and big planes always look slower. The camera they used is not helping to show any flight performance either.

Is this a market? I know exactly no one that flies turbine. I simply do not go to those sorts of fields. I imagine some may exist within an hours drive.

 

[Red]

I have no experience with this, but I have seen a few massive turbines that 3D. Pretty impressive shows. They look very jet like and appear to weigh almost nothing. They have thrust vectoring. They can do things you would not think a turbine could do. (I suspect they may be altering the thrust cone to get accerration when needed?)

I have noticed a small trend of turbine gliders similar to the Jeemax. For the most part these seem to be off shoots of the full glider versions of the models. They typically share the wing and tail with something else the company is already making. The performance of the Jeemax does not seem very impressive considering what has been invested into the model. She is a big girl though, and big planes always look slower. The camera they used is not helping to show any flight performance either.

Is this a market? I know exactly no one that flies turbine. I simply do not go to those sorts of fields. I imagine some may exist within an hours drive.

I fly turbines but yeah you've never been to my field. Justin Link and Justin Hall do as well. There is a very large contingent of turbine folks at Crows, Woodland and some of the other suitable fields.

Most turbine fly in's usually have more than one "glider" type there. I can't say for sure how big the market is. I would have a Jeemo if I did not fly off a dry lakebed, it would kill the belly. I need landing gear for sure, and I would think most folks would agree. For me I love the idea. Scale jets are cool, but when you want more graceful "pattern like" aerobatics glider types are much better suited. Another benefit is that since the gliders are so much cleaner, it takes less turbine thrust for the same or better performance which is cheaper.

Here is a good video that gives a better idea of performance of the Jeemo. This is with a K-45 motor that costs about $1700. Not much different than the high end EDF's.

 

[Doc J]

I fly turbines but yeah you've never been to my field. Justin Link and Justin Hall do as well. There is a very large contingent of turbine folks at Crows, Woodland and some of the other suitable fields.

Most turbine fly in's usually have more than one "glider" type there. I can't say for sure how big the market is. I would have a Jeemo if I did not fly off a dry lakebed, it would kill the belly. I need landing gear for sure, and I would think most folks would agree. For me I love the idea. Scale jets are cool, but when you want more graceful "pattern like" aerobatics glider types are much better suited. Another benefit is that since the gliders are so much cleaner, it takes less turbine thrust for the same or better performance which is cheaper.

Here is a good video that gives a better idea of performance of the Jeemo. This is with a K-45 motor that costs about $1700. Not much different than the high end EDF's.

Thanks for the Video, Red.

Heres my 5 cents, and please all note that I am trying to be very objective here; I'm NOT trying to put down the designs of others, rather I'm trying to point out what to me are simple faults in the design.

The video is not that well done, and not choreographed - so although it does illustrate the possibilities of the aircraft, or the aircraft type to some degree, its not that impressive. Its starts badly with that comical father with the dolly R/C that immediately has you muttering "Really?"

OK so lets take a closer look a the model itself.
As Red says - if you fly off a dry lake bed or maybe grass etc, the model needs some kind of landing gear, and obviously that model car dolly isnt it. As the video guys says; "I'd like to see him land it back on that dolly" (Or somesuch)
Also its very easy to pick up stones and dust with those obviously not well thought out low side jet intakes. The lack of landing gear on the Jeemo in the movie points to it having a different ancestry than the more recent one that is being used although this seems to have been fixed on the new "Jeemax".

If it was actually purposely designed to be an aerobatic jet glider, then - sorry, no.

The whole rear end stab arrangement of both the new and old model scream out "Why why why? to me, and as far as I can see there is no advantage of any kind in using the wing planform they have chosen.

So if I take another look at this one (Jeemax) - which was why it sparked my curiosity - then we get:

1. Fuselage:
Low side air inlets. Not recommended.
No designed-in U/C. It really needs something like the Salto and could then have brakes too.
The exhaust egress is a kind of slit along the lower rear fuselage which probably works OK in a straight line, but It needs Vectored thrust.
Rear and horizontal stabilizer mountings etc for this model are a mess.

2. Wing:
I looked at the wing from many angles, trying to imagine several possible advantages, but I have come up empty. This is just a design that the designer liked and with no attempt to make a really good aerobatic wing. I dont know what the section is, but I'm guessing some kind of semi-symmetrical.

3. Empennage:
Sorry, I dont think there is anything good to mention here, and maybe quite a lot that isnt.

So lets take a look at the new "Jeemax"

Its a much more choreographed video, but oddly again not so impressive. No "Wow!'s there.
As you can see the model can now ROG with a U/C (mounted in the wrong place) - did anyone notice another extra front wheel closer to the nose?

The engine used is obviously powerful enough, though no real attempt was made to show this in the movie. I like to see a bit of low throttle higher angle flight because I am well aware of what might happen if the models does not behave at low speeds. To complete the Aerobatics envelope it needs thrust vectoring, but with the design they are using this is next to impossible.

If its all boiled down, apart from the gimmick of being a purpose-designed aerobatic jet glider, its really nothing special.

BIG question from Wayne: Is this a market?

In Europe it has great potential as a lot of people have bought jet turbines for those big scale gliders to piggyback but soon discovered that piggy back does not work very well. Hence a lot of people now have a nice red box in their workshops containing a new almost never used Jet turbine. I bet there are a few in the USA too. I think most modellers love jet noise - even if they are glider guiders, so a good jet glider would be a great deal of fun for all.

I for one am interested, so I'll do a design study for a model that eliminates all of the obvious probems on the two present designs.

Basic Charter:

About 2.8~3M span with an efficient wing and aerofoil sections.
Much better organised and less draggy rear end Stab arrangement.
Much higher side jet intakes
Thrust vectoring
Designed-in U/C - maybe retract
Good looking.
Easy to acess the various systems.

Watch this space.

Doc.

 

[Wayne]

This is a pretty good video of a pretty light thrust vectoring setup. (Thank god they are smart enough to not use a Spektrum transmitter on something like this.)

There is a much better video of a guy 3D flying something similar.. but can't find it right now. It is amazing to me that turbines can do this sort of 3D flying where they are doing tail touches etc.. Lots of no air speed work.

These I assume are very different than what your goals are..?

To me I think you need to look at what the REAL advantages are of a turbine engine over other powered options, and then exploit those advantages as much as possible with your design.

I'm not sure, but I think the main advantage would be weight and size for a given amount of power?? Is that correct? Or are they just overpriced sound makers?

 

[Red]

This is a pretty good video of a pretty light thrust vectoring setup. (Thank god they are smart enough to not use a Spektrum transmitter on something like this.)

There is a much better video of a guy 3D flying something similar.. but can't find it right now. It is amazing to me that turbines can do this sort of 3D flying where they are doing tail touches etc.. Lots of no air speed work.

These I assume are very different than what your goals are..?

To me I think you need to look at what the REAL advantages are of a turbine engine over other powered options, and then exploit those advantages as much as possible with your design.

I'm not sure, but I think the main advantage would be weight and size for a given amount of power?? Is that correct? Or are they just overpriced sound makers?

This type of flying relies heavily on a flight controller (gyro) and thrust vectoring. It takes a massive amount of power and they are generally very draggy (and expensive) airframes. What interests me is the efficiency of a glider type design and the relatively low power required. Less brute force 3D and more graceful acro.

 

[Wayne]

I'm not sure that is a happy mix with a turbine? Hear me out. If you have a clean and efficient design it would not take much thrust before the airframe is simply going to accelerate to the thrust speed and the acrobatics become, well frightening due to the amount of energy in the airframe. AKA the first video in this thread. That model could probably be flown at half the thrust and still get to some silly speed, it will just take a bit longer to get there.

The video I posted was little interesting as the pilot performs a slow pass with speed brakes, lots of flap, rudders both facing out and vector thrust facing out and gear down to make the plane as draggy as possible for the slow pass, and still flies high alpha to pull it off.

So my question is how unlike a solid fuel rocket would a turbine be on a clean glider? Does the throttle really do much once you get the turbine ignited and the plane into the air? I'm assuming each landing would require the motor cut off?? Or do these motors have that much throttle control? (I guess thrust reversers might be a solution.)

Seems like you would be better off with an EDF except for the weight. This assumes there is a massive weight savings with a turbine?? I do not know.

 

[Doc J]

This is a pretty good video of a pretty light thrust vectoring setup. (Thank god they are smart enough to not use a Spektrum transmitter on something like this.)

There is a much better video of a guy 3D flying something similar.. but can't find it right now. It is amazing to me that turbines can do this sort of 3D flying where they are doing tail touches etc.. Lots of no air speed work.

These I assume are very different than what your goals are..?

To me I think you need to look at what the REAL advantages are of a turbine engine over other powered options, and then exploit those advantages as much as possible with your design.

I'm not sure, but I think the main advantage would be weight and size for a given amount of power?? Is that correct? Or are they just overpriced sound makers?

Hey Wayne - thanks for giving some thought to this.

I'm a bit inspired by the sheer number of people who have 4.5 to 7N jet turbines squirrelled away in their man caves. Frankly the real advantages in a model turbine are scarce when compared to maybe an EDF as you need fuel etc, and the ivestient cost is a bit high - note that I am only considering electric or turbine axial flow power as options here. But having said that, a high-end EDF is getting up there in price.

My (I have to admit still-evolving) intention isto to make a big, light, highly aerobatic GLIDER (not a scale jet) and put a jet engine in it. The big glider, 2.8 to 3.5M would be truly aerodynamically designed to give a really good performance just as an unpowered model - in which configuration it would still fly well. Say similar size to my Aresti 275 (118")

Because the jet engines are amazingly compact, the size changes for massive power increases are not that much different, so a well designed biggish (but very sleek) fuselage will work well . Development of the jet turbine since I was involved 20 years ago has been rapid and there are more and more choices avialble too.

For the model itself, actually, taking Gider.It as an example, they already have a quite a few oversized fuselage aerobatic models tht have and still do sell well; so its no real surprise to me that they went with a kind of adaptation of that theory there.

Added to the aerobatics requirement I'd for sure add thrust vectoring. You'd end up with a large VTPR model that could do virtually anything and the beautiful thing is that it need not cost the flyer and arm or a leg.

I will take care of all the visible probems I can see, with the available designs so far, and also a few that have been observed but not mentioned.

Thats about it for now but the thoughts are gelling in my brain rapidly.

Any thoughts anybody?

Chers,

Doc.

 

[Red]

I'm not sure that is a happy mix with a turbine? Hear me out. If you have a clean and efficient design it would not take much thrust before the airframe is simply going to accelerate to the thrust speed and the acrobatics become, well frightening due to the amount of energy in the airframe. AKA the first video in this thread. That model could probably be flown at half the thrust and still get to some silly speed, it will just take a bit longer to get there.

The video I posted was little interesting as the pilot performs a slow pass with speed brakes, lots of flap, rudders both facing out and vector thrust facing out and gear down to make the plane as draggy as possible for the slow pass, and still flies high alpha to pull it off.

So my question is how unlike a solid fuel rocket would a turbine be on a clean glider? Does the throttle really do much once you get the turbine ignited and the plane into the air? I'm assuming each landing would require the motor cut off?? Or do these motors have that much throttle control? (I guess thrust reversers might be a solution.)

Seems like you would be better off with an EDF except for the weight. This assumes there is a massive weight savings with a turbine?? I do not know.

Yes the throttle is fully functional, they will idle quite low. Not like a rocket motor at all. The idea is a much less than 1:1 thrust to weight ratio. You should come fly mine to give you some perspective. Lighter than equivalent thrust for EDF for sure, and as a bonus even lighter at landing.

 

[bubbasks]

Ive been on the fence for a jeemo. Really would like one as it combines both aspects of this hobby for me. I put in lots of turbine time and recently dove headfirst into gliders. But i keep getting the feeling it will end up being a novelty plane that i may get bored with. Kinda like my consendo evolution i use to fly. Loved it at first but didnt float well enough as a flatland glider and wasnt fast enough to pull at the speed addiction. Anyone have much time on one?

 

[Doc J]

Yes the throttle is fully functional, they will idle quite low. Not like a rocket motor at all. The idea is a much less than 1:1 thrust to weight ratio. You should come fly mine to give you some perspective. Lighter than equivalent thrust for EDF for sure, and as a bonus even lighter at landing.

Looking at what is available: I.e very few actual internal engine gliders - and what are flown with vectored thrust - which are normally large scale jet models, its easy to get mixed up. Added to the confusion are the piggy backs which most who have tried will tell you can a be a bit hard to deal with.

This is not a large twin-engined jet scale type model with vectored thrust.
Its a smallish 2.8~3m GLIDER model with a small internally mounted jet engine and vectored thrust - if desired.

From now I'm going to forget EDF and just concentrate on the Jet Turbine options

For a jet glider you dont need overkill in the power to weight department. Although if you listen to half of the pilots they will recommend outlandish sized angines. I was advised 7kg thrust for a 3M model for example.
A 3m model should only weigh 3 to 3.5Kg if made well. Light, stiff and strong. Maybe this is a hangover? The only Italian aerobatic glider models I have seen have been amazingly heavy - but I dont know why. They seem to use a lot of resin to make the job fast and easy I guess.

I'm seriously thinking of designing a lowish aspect ratio model - like my Aresti for example which is highly aerobatic - basically an Ahi type arangement. This would be about 2.8~3m span, around a single 4.5Kg Jet Turbine unit (which could be bigger if required) and a thrust vector unit. It would have intakes as far from the deck as possible, and a fixed or retract undercarriage - in the right place. Very likely a V-Tail - just to be different I'll admit - but that's not cast in stone yet.

Basic specs:

2.8~ 3.0M Low aspect ratio, high wing area "Ahi" type wing.
4.5K engine with a short nozzle to thrust vector option.
Fuselage designed to be a glider type but with a jet engine and an undercarriage (retract or not)
Maybe V tail.
Really good powered or unpowered aerobatic potential.
Hopefully good looking

This is where I am so far.

More suggestions?

Cheers,
Doc.

 

[Doc J]

Ive been on the fence for a jeemo. Really would like one as it combines both aspects of this hobby for me. I put in lots of turbine time and recently dove headfirst into gliders. But i keep getting the feeling it will end up being a novelty plane that i may get bored with. Kinda like my consendo evolution i use to fly. Loved it at first but didnt float well enough as a flatland glider and wasnt fast enough to pull at the speed addiction. Anyone have much time on one?

Hey Bubba - you need a "Jeemax" not a "Jeemo" as this is more like a jet glider.

But anyway please be aware:

1. The intakes are low and to the sides which is dangerous to a jet turbine engine picking up dust/gravel at 100,000 RPM.
2. The wings are not optimally designed and may be at risk of stalling at low speeds.
3. The undercarriage is not in the correct position and may not work at all unless another wheel is added.
4. This model cannot support thrust vector controls.
5. The vertical and horizontal stab are not optimized for the wing area
6. Expect it to be heavy and not so stiff.

The points listed are not cheap shots at someone elses' design, and each may have more or less influnce on the peformance of the model, but they are all true and they all exist.

Those are the things that caught my eye striaght away and actually gave me thr idea of making an Aeroic version.

Cheers, and I for one would ove to know how you get on if you do click the buy button.

Cheers,

Doc.

 

[bubbasks]

The only problem that personally keeps me from the jeemax is motor size. I believe the 70 size is a dead class. And limits an owner to select airframes on the light side of 80 class planes. If the jeemax had room for an 80 i believe ide buy one. Hence why i looked at the jeemo, the 45 class has many airframes it could go into if ever removed.

 

[Doc J]

The only problem that personally keeps me from the jeemax is motor size. I believe the 70 size is a dead class. And limits an owner to select airframes on the light side of 80 class planes. If the jeemax had room for an 80 i believe ide buy one. Hence why i looked at the jeemo, the 45 class has many airframes it could go into if ever removed.

I think the model must be quite heavy.

Doc.

 

[Wayne]

glider.it does make heavy planes. I imported a few of them a few years back. Was not at all impressed with quality, but the planes did fly well. Like James said, they were wet layups. Aerodynamics are also not a strong point in their design IMHO. With that said, I have seen some of their builds do some impressive shows of strength. They seem to be above average in that regard.

Red - thanks for setting me straight on the throttle question.

Following to see what develops. Maybe some other turbine folks will pop up and give some feedback.

 

[Doc J]

glider.it does make heavy planes. I imported a few of them a few years back. Was not at all impressed with quality, but the planes did fly well. Like James said, they were wet layups. Aerodynamics are also not a strong point in their design IMHO. With that said, I have seen some of their builds do some impressive shows of strength. They seem to be above average in that regard.

Red - thanks for setting me straight on the throttle question.

Following to see what develops. Maybe some other turbine folks will pop up and give some feedback.

Thanks, Wayne.

OK more thoughts form me.

The market:
I have been talking to a few people on the jet engine forums to gather their thoughts and the general feelling there is that there is a market, and potentially quite a strong one. I'm going to do some more follow up work here with a design sketch probably next week.

The engine:
There is vastly divided opinion on engine size - as Red had told me was the case with the jetsters - with the guys flying the fast big scale jets going for very high P/W ratios, but I think that's because they are generally flying pretty heavy draggy planes that dont glide worth a hoot. Many of them dont have any experience of a gider at all and base their opinions around wingspan only.
A 2.75M wingdspan scale jet is a big bugger!

So in this case I am going to forget asking for that kind of advice and just go scientific on the engine size.

Model Size:
Its my intention to make a model that is not too hard to transport; not more so that a conventional 3M glider got example. In this case, the wife and kids hae some possibility of getting in the car too.

I'm going to make a light strong model with a pretty large wing area - kind of a jet VTPR if you will. I'll go for a power/weight ratio of a bit better than 1:1 so for a span of 2.75M (108") and a (Largish) projected wing area of around 1,581 In/2 (102dm/2) I'd expect to make a model about 3Kg empty and 4Kg ready to go. This means I need a 4K engine. Then to give margin enough to enable controllable hover manoevers, that would mean a 4.5K engine, so thats where I'm going.

Vectored thrust:
Regarding the vectored thrust, doing a few sums, I have found out that this is not as predictable as might be thought at first. Problems are mainly due to the compressibility of air, plus the differential heat involved. The further away you have your vector unit from the Jet exhaust nozzle, the less effective it will become and can even theoretically start to get a resonant pulse going, rather than clean diversion of heated air. The nozzle needs to be as close as possible to the engine and make exit as fast as possible in order to do the best job.

Model Configuration:
OK so that cuts out most of the possibilities where the exhaust would exit from the long tail of a "scale" type model - such a s Salto for instance. The Jeems and some EDF have addressed this with a lower rear exhaust, but its still long, and TBH the way it has been done could lead to vectoring (pulse) problems - if it doesn't aready.

So how?
So my proposal will be to put the engine under the wing with upper intakes and the fuselage cut there to form a nice cowling and the vector unit for the most part out in the breeze immeditely behind the engine. This let me get a good strong built-in U/C just in front of the CG where it should be, and I wont have to make several attempts at that. (As the Jeems seem have done)

The back end:
A few more sums have led me to abandon the thoughts I had of being different with a V-tail. With the exhaust exiting mid-fuselge there is little danger of the tail getting hot, plus there could be a bit of nasty interaction with a Vee as the model has essentially become a pod and boom configuration.

Does all this make sense? It's me stacking, adding and subtacting all the aerodynamic and must have Jenga bricks around as I do with any design until something practical emerges. Once all the bricks are there, I can then put pen to paper and make an efficient and hopefully good looking model.

Unfortunately I think this will be the very first specially/specifically designed Jet powered aerobatic GLIDER.
There is nothing to learn from the Jeemo/Jeemax as they both seem to be adaptations or compromises of one description or other.

Thoughts anyone? More brains = more horsepower.

Doc.

 

[Wayne]

Hope you are taking my comments as a fun bit of feedback on the overall concept. I'm still trying to fully wrap my head around the goal.


Correct me if I am wrong, but doesn't the vectoring need to be at the rear of the plane for much effect? I'd think this layout would be rather lacking:

Sure it is eye catching.. but thrust vectored?

Does "glider" and "controllable hover maneuvers" really cross over very well on the same airframe? Seems to me those 2 goals pretty much oppose one another..?

Also having flown models with thrust vectoring - they are kind of a gimmick. They take a LOT of time to show any level of mastery with. Sure, it is easy to do silly things with, but to get it down to an artistic level of control, pilots do require a LOT of practice with any given airframe. I don't think I have seen any of my flying buddies stay with thrust vectoring much past the novel stages of playing with it. Maybe not even a selling point at this price point?

A delta wing is VERY forgiving for this sort of play, and can be VERY strong. I'd think this a very hard to achieve goal with a high aspect ratio wing at these weights able to handle high Gs and still be an efficient glider like wing..?

Without the vectoring, you have my interest.

If anyone can do this it is Hammond. He has surprised me on more than one occasion! The Gremlin is a great example- those planes were a lot of fun to fly and did things I thought not possible for them to do.

 

[Hoqiam]

Hey Doc,

How about a P-38 style vehicle with an early version of a MARS LANDER inverted V tail where the tips of the
inverted V would attach to the booms. The engine could fit into the cockpit bubble and the exhaust vector
immediately behind it. And of course glider style wings. The landing gear placement would be a "no brainer".

Tom Strom

 

[Doc J]

Hi Wayne - more below:

Hope you are taking my comments as a fun bit of feedback on the overall concept. I'm still trying to fully wrap my head around the goal.

I hear you there. Goal is jet powered VTPR style glider.

Correct me if I am wrong, but doesn't the vectoring need to be at the rear of the plane for much effect? I'd think this layout would be rather lacking:

Sure it is eye catching.. but thrust vectored?

Actually the fulcrum for any manoeuvre is based around the CG/MAC positions on the wing or about 40% of most glider wing chords. The further you put the vector back - the more leverage it has, but it takes more time to have effect. Nearer the CG is therefore more effctive.

Does "glider" and "controllable hover maneuvers" really cross over very well on the same airframe? Seems to me those 2 goals pretty much oppose one another..?

Well they are sure different goals, but I am not sure they are opposed.

Also having flown models with thrust vectoring - they are kind of a gimmick. They take a LOT of time to show any level of mastery with. Sure, it is easy to do silly things with, but to get it down to an artistic level of control, pilots do require a LOT of practice with any given airframe. I don't think I have seen any of my flying buddies stay with thrust vectoring much past the novel stages of playing with it. Maybe not even a selling point at this price point?

OK one thing I have been remiss on here and that is to point out that the idea is that the model should be capable of using thrust vectoring as an option = not a requirement. I apologise fo this as I did not make it very clear.

The idea is to make a model with a jet engine with the CAPABILTY. ie configuration that would allow for the thrust vectoring unit to be used.

A delta wing is VERY forgiving for this sort of play, and can be VERY strong. I'd think this a very hard to achieve goal with a high aspect ratio wing at these weights able to handle high Gs and still be an efficient glider like wing..?

I agree on the suitabiity of a delta for many good reasons, but I also know that a lot of people dont like deltas for not so many good reasons. I'm totally sure I can make a light, strong very high G wing. I have the Sine Wave Spar and that makes it all a lot esier.

Without the vectoring, you have my interest.

Well as I sad, if the model CAN have a Vector unit fitted, then it has that capability - to no detriment of the rest of the model or its performance, and just as a user choice.

If anyone can do this it is Hammond. He has surprised me on more than one occasion! The Gremlin is a great example- those planes were a lot of fun to fly and did things I thought not possible for them to do.

Why thanks, Kind sir. I do my best.

Actually the new jet plane - now called SUNFISH would end up looking not so different from the Gremlin. Just a tad larger (!) I would be happy if it could also do those Vertical catherine wheel spins like the Gremlin too!

Chatting about the design and converging on this forum is one of life's good things to me, so thanks for that.

Lets have some fun 'because that's what its all about.

Doc.

 

[Doc J]

Hey Doc,

How about a P-38 style vehicle with an early version of a MARS LANDER inverted V tail where the tips of the
inverted V would attach to the booms. The engine could fit into the cockpit bubble and the exhaust vector
immediately behind it. And of course glider style wings. The landing gear placement would be a "no brainer".

Tom Strom

What are you thnking, Tommy? I cant get it into my pea-brain. Can you make a sketch?

Doc.

ALWAYS OPEN TO NEW IDEAS