What's new
By:
Aloft Forums

Welcome to Aloft Forums. Register a free account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members through your own private inbox!

Aeroic Gremlin, build (Aeroic donation to the 2019 ISR)

I take it that snark to indicate that you might think I'm asking too much for continual process improvements.

Many of these "improvements" will not add to unit cost. But will differentiate Aeroic as a leader "vendor of choice" in the mid moldie price range.

Yes, some are personal preference issues. But it can't hurt (much) to ask.
 
It hurts it hurts...owwww!

Of course, added to the excellent suggestions of retractable landing gear (11b-rev2) and soft ice cream capability (15a-rev4), and the new kitchen sink compatibility, (16c-rev1) Kloud Blaster (Mk 9 series2) will conform to the latest edict of being built in a completely sterile environment by robots (in government approved and tested masks and white coats) and will therefore be 100% Covid-19 safe (12-2-1 Rev 6). Now I'm thinking of adding the bold statement of "Unbreakable in flight" too. As you wont be able to fly it anyway.

Actually I like this kind of thing - some good suggestions have been made, and anyway we need as much fun as we can get these days.

(and it still hurts...:ROFLMAO:)

Doc.
 
Gremlin in the yellow corner, and Minivec in the red corner. Some really cool flying from James Clarke in the UK - verdict? Gremlin is quicker.

Info: Having reached the extreme dendritic limits of my facetiousness I have decided not to name this little blighter "Kloudblaster" after all. Thats too much even for fun-loving me. Sooo...the all new, all singing, all dancing, and highly improved version of this magnificent flying machine will be called...

"Zanzara"

Which as all us who speak fluent Italian, among whom I am excluded, will know, means: Mosquito.​

 
Last edited:
Alright finally some video of the Gremlin in some big air!

Both look like they were fun to fly. But I hate to say it, in this video the mini Vector looked to be carrying a bit more energy. Do you know if they were both ballasted close to the same. I think the Gremlin would have come off a bit better with more knife edge flight.
 
Oh, that was without rudder!

Also as I read the specs the mini Vector is 1.69m. So the Gremlin is at a real size disadvantage. But it really didn't look to be that bad.

Still waiting for some wind and in the correct direction to maiden my Gremlin.
 
Last edited:
Konrad, Guys, there was a lot of shit swirling around about this little whizzer going on RCGroups, mainly from two known Trolls. This model was meant, specifically, to be a quirky looking small aerobatic model, easily dissembled, that could be chucked in the back of a car, or on a parcel shelf to be used when the flyer had a bit of spare time, or was passing a likely looking site - hence "BIBOC" - Bung In Back Of Car. Its not a VTPR "Flipper" and was never meant to be - though many seem to have thought it was. It is, and it does what it says on the tin. As far as I know, until now, I have never made a model that does not do exactly what its supposed to do.
 
I have to admit that I too thought that "Freestyle" meant something like VTPR. And there is no way this model would meet that type of flying as it weighed too much. You cleared that up early in this thread. It looks to be more that adequate as a high lift aerobat and the last set of videos proves that.

Also those that have actually flown one, all seem to like how the Gremlin flies. Some don't think it is unique enough to keep in their stable as they have a mini Vector. But that is more of a storage issue than a flying one.

Not sure what kind of issue those guys have. If they want a fully molded VTPR they should try their hand at bringing one to market.
 
Last edited:
Finally had some good air to maiden the Gremlin in. It wasn't a big lift day, but good air. The wind was in the 25mph range . On the east face of the SLoT. I had to wait until the sun was setting. This wrecked havoc with visual orientation. The good news was that the Gremlin was very stable while I waited to figure out what was what. This Gremlin is only one of the few models that flew straight out with no trim changes to the basic flight controls. I can say that the aileron differential is close to 1:1 with the symmetrical airfoil and that large vertical fin. I will need to add some expo to the ailerons.

Elevator response was fine maybe a bit sensitive. Inverted flight took very little forward stick. These two observation might indicate that I need to add 15 grams of nose weight. I've been waiting to maiden the Gremlin for so long I had forgotten to add my customary nose weight for maiden flight. This might explain not needing to trim the elevator.

Now to the magic of the Gremlin the rudder. WOW! very good power for rudder stall turns. there is very little (none that I could see from just one flight) rudder coupling. There wasn't enough lift to sustain knife edge flight from horizon to horizon . But the rudder did keep the nose up. I have to admit snaps are wild, maybe too wild. But the gremlin stoped tumbling as soon as a let off the sticks.

Stalls are non-events. Just let go of the sticks. I did at times have to push forward stick to regain flying speed. (I like the balance set like this but many like a bit more nose weight).

She is no light weight but I was able the practice coring thermals, again the Gremlin was very stable.

Landing was a pussy cat with the crow working great. It wasn't the smoothest landing I've ever made as I was staring into the sun. But I had good roll authority. And I could slow down rather well.

The Gremlin is a fun ship. I still need to work on my snap flaps and finding a good balance between the high rate and low rate throws. I still want to play around with the CG but I know I'm with in 15 grams of where I'll ultimately put the CG for sport flying.

I only got in one 10 minute flight as I was racing the sun.

There was one problem that did come to light. I had allowed the rudder to hang ever so slightly below the fuselage as a result of the landing slide out I broke one of my rudder hinges. This hit goes against me for not noticing this when I made the center hinge rudder. I'm going to add a bit of a tail skid to protect the rudder hinge.

I can't for the life of me understand why some folks had issues with the model. On face value it does what it says it is, an aerobatic Freestyle 60". By the gram scale she is a bit heavy for what most would think a 60" aerobatic model should weight. But on the wing this 1.65 kg model felt light and aerobatic. The weight appears to add power to carry through the aerobatic manuvers. Not so much as to act like a bulldozer. But with a nice ratio of weight to drag. For example I did a series of horizontal snaps, and by the end of the 3rd rotation the Gremlin was flying backwards from all the control drag. Most ships by the end of 1.5 rotations have dropped the nose and are heading towards the ground.

I still have to do some fine tuning to get the smooth big air flight we all like from these FreeStyle ships. But this one flight does prove that she flies and flies rather well.

I would like to thank Doc. Hammond for his donation the 2019 ISR!

Looking for some big air. (After I fix the Rudder)

All the best,
Konrad
 
Last edited:
Konrad said:
Finally had some good air to maiden the Gremlin in. It wasn't a big lift day, but good air. The wind was in the 25mph range . On the east face of the SLoT. I had to wait until the sun was setting. This wrecked havoc with visual orientation. The good news was that the Gremlin was very stable while I waited to figure out what was what. This Gremlin is only one of the few models that flew straight out with no trim changes to the basic flight controls. I can say that the aileron differential is close to 1:1 with the symmetrical airfoil and that large vertical fin. I will need to add some expo to the ailerons.

Elevator response was fine maybe a bit sensitive. Inverted flight took very little forward stick. These two observation might indicate that I need to add 15 grams of nose weight. I've been waiting to maiden the Gremlin for so long I had forgotten to add my customary nose weight for maiden flight. This might explain not needing to trim the elevator.

Now to the magic of the Gremlin the rudder. WOW! very good power for rudder stall turns. there is very little (none that I could see from just one flight) rudder coupling. There wasn't enough lift to sustain knife edge flight from horizon to horizon . But the rudder did keep the nose up. I have to admit snaps are wild, maybe too wild. But the gremlin stoped tumbling as soon as a let off the sticks.

Stalls are non-events. Just let go of the sticks. I did at times have to push forward stick to regain flying speed. (I like the balance set like this but many like a bit more nose weight).

She is no light weight but I was able the practice coring thermals, again the Gremlin was very stable.

Landing was a pussy cat with the crow working great. It wasn't the smoothest landing I've ever made as I was staring into the sun. But I had good roll authority. And I could slow down rather well.

The Gremlin is a fun ship. I still need to work on my snap flaps and finding a good balance between the high rate and low rate throws. I still want to play around with the CG but I know I'm with in 15 grams of where I'll ultimately put the CG for sport flying.

I only got in one 10 minute flight as I was racing the sun.

There was one problem that did come to light. I had allowed the rudder to hang ever so slightly below the fuselage as a result of the landing slide out I broke one of my rudder hinges. This hit goes against me for not noticing this when I make the center hinge rudder. I'm going to add a bit of a tail skid to protect the rudder hinge.

I can't for the life of me understand why some had issues with the model. On face value it does what it says it is, an aerobatic Freestyle 60". By the gram scale she is a bit heavy for what most would think a 60" aerobatic model should weight. But on the wing this 1.65 kg model felt light and aerobatic. The weight appears to add power to carry through the aerobatic manuvers. Not so much as to act like a bulldozer. But with a nice ratio of weight to drag. For example I did a series of horizontal snaps, and by the end of the 3rd rotation the Gremlin was flying backwards from all the control drag. Most ships by the end of 1.5 rotations have dropped the nose and are heading towards the ground.

I still have to do some fine tuning to get the smooth big air flight we all like from these FreeStyle ships. But this one flight does prove that she flies and flies rather well.

I would like to thank Doc. Hammond for his donation the 2019 ISR!

Looking for some big air. (After I fix the Rudder)

All the best,
Konrad
Click to expand...

Pics, Konrad, Pics!

Glad you like the little monster, and yes I was surprised by the negative reactions to it - I think its because it came out among a rash of VTPR flippers and being generally of the same kind of dimensions people thought that it was a flipper too.

BTW the new ones are 250 to 300 grammes lighter than the (Zhou made) one you have.

Interesting to tell you why: The first Gremlins were made in Zhou's "New temperature controlled factory" - which actually did not exist - especially the temp control part. So the models were made in the depths of a Wuhan winter with only a couple of paraffin's heaters available. The temperature was always close to freezing which must have made the resin like toothpaste, until the mixed batch was heated up in hot water - which makes the pot life just a very few minutes so you can imagine how much was used.

Yaaahhhh!

Pics...pics!

Cheers,

Doc.
 
I think mine was of the last batch from Zhou, in that mine came out about 300 grams lighter than the original batch. If the new models are 200 plus grams lighter that is great. Mine came out a bit heavy as I added too much weight with my rudder wipers. Now that I've damage the rudder (hinge) I think I'll take the time to try my hand at redoing the wipers. To be honest I think this model needs the weight to help power through the large big lift maneuvers. Like you said this is NOT a VTPR type plane! Trying to fly her like one would resemble the hippos in Fantasia

I assume you want in flight pics, rather than those of my ripped off rudder? My maidens always look bad as I'm testing dif, expo, mix etc. Later the flights can start to look better, maybe even graceful. Maybe I can get some video or better yet get a better pilot to throw her around.

I think it is a mistake to not take the weight hit to add rudder. While I had a bit of wind, I didn't have a lot of lift. It was a lot of fun going vertical and doing a hammer head just like I do with my powered flat land ships. That is with the Gremlin I can go vertical, true vertical, near the top kick the rudder and watch her rotate around. With most gliders I have the bias the vertical line to the way I want the model to rotate and then hope it will rotate not just flop in the direction of the biased line.

I do want to thank Mo for the "Mo mount". That is one of the keys to getting control I wanted and saving a bit of weight in the back with both servos in the back.

As this is a big air type ship I think I'll place an order for some brass rod for my ballast. Not that the model needs it but that it is another tool to use in setting up the Gremlin to fly her best.

Doc, I will try to get you some videos but that means flying with folks. As an introvert (lone flier) that might be difficult.

I really don't know anything about the glider market. But if the new design addresses the 3 minor issues (servo opening, elevator rod leverage and wing retention) with the motor option it should own its market sector.

Again thank you for the donation to the 2019 ISR.
 
Hi Konrad, actually any pics would be great, flying, static, anything. I just want to record the little devil for posterity because there will not be any more exactly like that.

The new model, completely re-vamped, will be called "Zanzara" and addresses all the problems, and includes most of the suggestions from various sources, as well as being instantly electrifiable.

Control sensitivity:
I guess you are now seeing the results of using a high response section. I'm not sure I'd describe the response as "Sensitive" though many people have, but its more like "Assertive". I used this section for the Arestis and the Gremlin simply because I could find nothing better anywhere. You just get more bang for the buck as you don't need so much control movement to achieve the same responses, and that means less drag and more energy to play with.

Trimming:
Best way to get it right is to keep the CG at the "sensitive" position, then play with the control movements and the control setups on the transmitter with differentials and expos. The CG "deadening" method might. not be the best way to go here.

Why use this type of section?

Energy retention:
I have flown several symmetrical section aerobatic models, and either the section is too thin to give good aerobatics, or its thick enough, but as soon as you operate any control it quickly runs out of steam and the model flutters from the sky. As we know well, the key to good big air aerobatics is energy retention. Anyone who has seen an Aresti 108 fly will be amazed at how, during a hammerhead climb (Or "stall turn" and we Blimey Brits call them!) it simply goes up...and up...and up...without ballast - and then when you do get the lead out...woo hoo!

Ballast:
Another advantage of using these sections is their ability to carry ballast. Normally this is a function of camber/thickness, but we tend to forget that each time we make a control input, we are actually introducing camber.

How does it work?:
The shape of the JHSYM foil series works like my other "double cusped" sections, its just symmetrical so the same top and bottom with no camber. Basically the air is being persuaded not to leave the lifting surface (Boundary layer separation) quite as early as most others, because there is cusp which changes the pressure just a little bit. Of course this little bit changes too, and increases with speed. So although the lifting surface changes (Upright/inverted flight) the actual performance of the aerofoil, unlike a semi symmetrical set up, remains is the same at all times. The result is better control

So the net result list is:
  • More control response for less drag.
  • Better energy retention.
  • Thickness is suitable for really well controlled aeros.
  • Ability to carry higher ballast loads.
I'm not sure if all that makes good sense as I blurted it down as it came to me.

Cheers,

Doc.
 
Last edited:
Yep, the ailerons are fast early in their motion. Full throw as set up results in a nice roll rate. So it looks like the airflow over the ailerons has more energy than a normal airfoil, early in the aileron motion. This is why I think I need more expo. I normally don't like Expo. (I'm old school, in that in my day if you wanted expo you had to use audio pots on your sticks. I learned to fly with linear pots).

This energy is why I think there is little need for differential in the set up.

As to CG, I have it set to where I think the aft point is. When slowed down I did get the tail to sink slowing down the ship even more. (Looked like the Gremlin was going to enter a deep stall). I could get the speed back but I had to add down elevator. I agree that adding nose weight to tame being overly sensitive, is the wrong way to control elevator response. If the elevator is too responsive cut down on the throw or add Expo.

I think I was close to the limit of stability in that the model was hunting in pitch, ever so slightly. I need to play around with things to make sure it isn't a linkage issue or aileron rigging issue.

I have only one flight on this model and less that 10 minutes of flight time. So there is a lot more to do in fine tuning the model.
 
Looking good!

I'm waiting with baited breath (fish for dinner) for the next instalment...

and heaven forbid! (Help...scream!!!) Wayne's maiden!

Anyway at least the model is being flown and developed as it should be.

Cheers,

Doc
 
I think you need to give Wayne a call! I think he has gone through 2 or 3 Gremlins now. (Read somebody made him an offer he couldn't refuse)!
 
Konrad said:
I think you need to give Wayne a call! I think he has gone through 2 or 3 Gremlins now. (Read somebody made him an offer he couldn't refuse)!
Click to expand...

Why that scallywag! It would not surprise me at all.

Actually I think the only planes Wayne keeps are those he doesn't like. The others suffer unplanned sudden flight terminations, or get scooped by eagle eyed customers.

Doc.
 
Yeah, a customer bought it a couple of weeks ago before I got to fly it. It was the plane I was most looking forward to, but had a customer that really wanted a Gremlin and prefered a built one, so I let it go.
 
You must log in or register to reply here.

Similar threads

Konrad
ISR 2019 in the history books
Replies
5
Views
3K
Doc James Hammond
Doc James Hammond
Back
Top