Redshift; Used Purchase

[Konrad]

Oh the joys of an optimized wing planform...Tail will wiggle a bit, Konrad - its a tad too small.

As you have observed, Its nice how the model thermals well and just tracks in for landings without too much wing waggling - I can tell you that most people when they first saw the wing shape, were very quick to forecast dire consequences - but then they didn't know that I had tested it.

About the only thing thats not changed on the New Redshift "Spada" model is the wing.

What a lovely day's flying. Glad to see its keeping you amused!

Cheers,

Doc.

I have to admit that the narrow tips scared me. But after talking with you and how the double cusp airfoils worked I was actually looking forward to seeing how the wing performed.
The wing is not magic in that one can drive it to stall. But the stall appears to be delayed and surprisingly mild with the CG at neutral trim per the dive test. I think I mentioned that I did drive the RedShift into a high speed stall through a base pylon turn. She just opened up the radius and dropped the nose into a slight spin. No flick roll like we classically see with the pylon turn induced tip stall.

Again as you mention the V-tail was a bit small as I had to actively get out of the stall induced spin.

Now I'd like to see two changes to the new Spada wing. I'd like the flap servo pocket allow for 35mm x 30mm x 10mm servo without hitting the wing box. I'd like to see if the sine wave spar and aileron pocket be moved to allow 10mm thick servo (30mm x30mm x10mm). This is more a sales consideration as the KST X0-8+ have been fine on the ailerons. They did not strip in my crash. Also at this level of model (performance) I'd like to see the control horns left off. We all have our own ideas as to what is the best way to actuate the flaps and ailerons.

Like you said if there is a design flaw it is in the V-Tail, that is the control geometry and effective vertical area. In pitch she felt great. I think a couple percent larger area and a slightly narrower V angle and the Redshift's control problems will be addressed.

To be clear most of these concerns are really just preference on my part. Other than the geometry in the V-tail control system there is little of design that needs to be changed. Yes, I'd like to see a bottom feeder servo tray and a narrower fuselage. But again these are personal preference issues.

Now you and Wayne mentioned that the Redshift had a unique ripping sound. In the light lift I was flying in I did not hear this. In fact the RedShift was almost silent making a whisper noise. The Stregas in the same lift (and going a bit slower) did make the classic swish we love to hear.

With the new OEM and design improvements I'm looking forward to trying out the new RedShift Spada.

Doc. early on in this thread I think you said there were 5 major design improvements with the RedShift over that of the Strega. I think I found 4. Could you share what you were thinking when you put pen to paper with this design?

 

[Konrad]

Doc, I'm just a hack of a pilot with some engineering background. I also know that the 2019 British F3F team used the RedShift. Can you share this feedback with us. I ask as I'm starting to build my second Redshift and wonder if there is anything I missed that the skilled pilots might have noticed. Now would be a good time to make adjustment to my build.

I've repaired the shipping damage to the wings and removed the wing and V-tail control horns. I will be doing the V-tail flip mod. I'm also thinking of adding a 20mm x 22mm fuselage carbon ballast tube to keep the roll inertia to a minimum. (This is for front side F3F sloping. None of my F3F ships will be DS'd, well not as long as I own them)!

 

[Doc James Hammond]

Hi Konrad - I'll deal with this, one by one as you have written it below:

I have to admit that the narrow tips scared me. But after talking with you and how the double cusp airfoils worked I was actually looking forward to seeing how the wing performed.
The wing is not magic in that one can drive it to stall. But the stall appears to be delayed and surprisingly mild with the CG at neutral trim per the dive test. I think I mentioned that I did drive the RedShift into a high speed stall through a base pylon turn. She just opened up the radius and dropped the nose into a slight spin. No flick roll like we classically see with the pylon turn induced tip stall.

I think any wing can be driven to stall. I really do prefer one that behaves itself for the most part except when driven though, as the good behaviour lets you concentrate on the flying bit without worrying about the possible consequences of over doing it.

Again as you mention the V-tail was a bit small as I had to actively get out of the stall induced spin.

Now I'd like to see two changes to the new Spada wing. I'd like the flap servo pocket allow for 35mm x 30mm x 10mm servo without hitting the wing box.

Done.

I'd like to see if the sine wave spar and aileron pocket be moved to allow 10mm thick servo (30mm x30mm x10mm).

Done, and now with new 8mm servo trays too - if you want to use the 8's.

This is more a sales consideration as the KST X0-8+ have been fine on the ailerons. They did not strip in my crash. Also at this level of model (performance) I'd like to see the control horns left off. We all have our own ideas as to what is the best way to actuate the flaps and ailerons.

I could do that, but when I tried it with the Schwing many moons ago, I was met by a barrage of invective screeching at me to reinstate them. Tell you what - I'll leave yours out!

Like you said if there is a design flaw it is in the V-Tail, that is the control geometry and effective vertical area. In pitch she felt great. I think a couple percent larger area and a slightly narrower V angle and the Redshift's control problems will be addressed.

The bigger tail will take care of it - its about another 8% each side.

To be clear most of these concerns are really just preference on my part. Other than the geometry in the V-tail control system there is little of design that needs to be changed. Yes, I'd like to see a bottom feeder servo tray and a narrower fuselage. But again these are personal preference issues.

Now you and Wayne mentioned that the Redshift had a unique ripping sound. In the light light I was flying in I did not hear this. In fact the RedShift was almost silent making a whisper noise. The Stregas in the same lift (and going a bit slower) did make the classic swish we love to hear.

One day it will suddenly start and surprise you - I thought something was loose the first time I heard it - I love it more than the swish.

With the new OEM and design improvements I'm looking forward to trying out the new RedShift Spada.

Doc. early on in this thread I think you said there were 5 major design improvements with the RedShift over that of the Strega. I think I found 4. Could you share what you were thinking when you put pen to paper with this design?

1. NO Bloody incidence - so no ballooning turns. (RCRCM put this in without telling me they changed the design which was 0-0)
2. Better aerofoils faster at the top and slower at the bottom.
3. Optimised wing planform - lift where it should be and not in other places.
4. Better Stab foil - more response for less movement - overall less drag.
5. Wing ballast.
6. Sine wave spar.

Thats it.

Doc, I'm just a hack of a pilot with some engineering background. I also know that the 2019 British F3F team used the RedShift. Can you share this feedback with us. I ask as I'm starting to build my second Redshift and wonder if there is anything I missed that the skilled pilots might have noticed. Now would be a good time to make adjustment to my build.

Not really Konrad. I was told that the Rugen site in 2019 was highly "localised" - I mean it needed a lot of local knowledge and previous flying experience to get the most from it. Maybe a bit like our Long Pan site in Taiwan where Mr O can beat his own records there, but only using a really heavily built Needle, which flies well nowhere else. Yes he can make good times elsewhere but not with the Needle and no show stoppers.

I've repaired the shipping damage to the wings and removed the wing and V-tail control horns. I will be doing the V-tail flip mod. I'm also thinking of adding a 20mm x 22mm fuselage carbon ballast tube to keep the roll inertia to a minimum. (This is for front side F3F sloping. None of my F3F ships will be DS'd, well not as long as I own them)!

Good luck with the new MK1 - but Spada is coming and its coming with some new features which I'm sure you'll love.

Cheers,

Doc.

 

[purview]

Always good news if things can progress. Limitation factor number one is – why not – the piloting skillz in uncertain environments. As it is not easy to deal with the elements, it is good to know that materials are not worrying about the possible consequences. ?

The localization pros and cons are another type of limitation to all endeavours of keeping our planes alive.

As I may have the possibility (due to uncertainty of the Covid-19 spread) to compete with my own Redshift, I made up the game plan for the Donaupokal on 15th of May. As I'm still a novice, I try to get my first countable sub40 PB and then I switch to the Redshift to collect more confidence of the plane (and of course of my stressed self) under competition rules. Winning is currently not in reach so keep wallets closed ?. The proof that I'm not joking on myself: I practice with guidance of this this training advices and deep dark online digging for some holy techniques:

F3F improvement - Have a plan !

Articles – GBSRA

www.gbsra.co.uk

Have Fun! Totally Unlocated and FREE of all our sins is the main goal...

 

[Konrad]

Like you I'm still not equipment limited!

Prior to Wednesday I think I had a total of of less than 4 hours of sport flying on all my 3 meter F3F racers. Often times I was still trimming the model from the last repair while on the race course! SWMBO (the wife) keeps laughing at me that I allow racing to interfere with my flight testing. She is not wrong.

P. S.
You land on the front side (face), down wind?

 

[Konrad]

I don't know why I admit to these failings. Today I spend a bit of time sport flying my F3F ships, as the coastal race was canceled for fear of fog. Lift was good at the SLoT so I was able to add 310 grams of ballast. The Redshift handled the light ballast load just fine. But when I was in thermal mode I occasionally got a wicked stall. I spent the whole flight looking for a safe camber setting that would alleviate this wicked stall. I never found it, so I set up to land.

On the ground I noticed that in thermal mode my ailerons drooped more than my flaps. This gave my wing wash in when in thermal mode. Wednesday I was working with a lighter wing loading and/or never got slow enough to notice this wash in. After reprograming my thermal camber settings, on subsequent flight had the thermal mode responding as well, actually better than she was on Wednesday.

So what did I learn? That after any major repair one needs to go through the whole program to make sure the control surfaces are responding as one expects. The fact that I had to re-hinge all the control surfaces meant that the servo curves all needed to be re-adjusted a bit. This is because with the small control arm length of this design and the use of IDS any slight change in hinge geometry has a huge effect on how the control surface will respond.

 

[Konrad]

OK, after spending some time Saturday sport flying my Redshift. I have some questions. Are the set up spec's those of Mr. "O"? I ask as I'm having some problems getting the Redshift to consistently groove through the turns.

Per the dive test I like the CG a bit aft of where indicated in the set up sheet. It is looking like I may need more aileron differential than indicated as at times my tail is dragging low through the turn. But if I do add more aileron differential my roll rate suffers. I can't as of yet up the aileron deflection as they bottom out on the wipers limiting the up motion of the aileron. (I've now removed some of the wiper).

I'm thinking of adding some rudder mix (8 points) with the aileron to help pick up the tail in the turn (overcome some adverse yaw). I normally don't like to do this as the amount of rudder mix is highly dependent of airspeed. But as has been noted the V-tail is a bit on the shy side on area.

Also with my CG I'm finding that the 5mm snap flap is way too much.

So with the passage of time have others (the British F3F team) come back with different set up values. I know a lot of this is personal preference

Next time out I'm thinking of moving the CG forward and seeing how she responds. But I do like how the Redshift holds the line in knife edge at the current CG..

 

[Konrad]

Durring Saturday's sport flying session I hate to admit it but I again landed behind the hill in the rear rotor, twice! I'm happy to report that the repair to the torn out wing box held up just fine. Please forgive me for bragging a bit, but it looks like the wing is now adiquately repaired. Now I just need to learn to stay out of the rear rotor at the SLoT!

Please note how the stess relief radiuses helped keep the damage to the fuselage to a minimum. Yes, the wing joiner did crush the front of the joiner opening and there was a slight stss crack in the upper rear corner from where the wing tried to twist the top off the fuselage before the wing box tore out. You might recall what the damage looked like by going back to page 12 (post 225 and post 235)

 

[Doc James Hammond]

OK, after spending some time Saturday sport flying my Redshift. I have some questions. Are the set up spec's those of Mr. "O"? I ask as I'm having some problems getting the Redshift to consistently groove through the turns.

Per the dive test I like the CG a bit aft of where indicated in the set up sheet. It is looking like I may need more aileron differential than indicated as at times my tail is dragging low through the turn. But if I do add more aileron differential my roll rate suffers. I can't as of yet up the aileron deflection as they bottom out on the wipers limiting the up motion of the aileron. (I've now removed some of the wiper).

I'm thinking of adding some rudder mix (8 points) with the aileron to help pick up the tail in the turn (overcome some adverse yaw). I normally don't like to do this as the amount of rudder mix is highly dependent of airspeed. But as has been noted the V-tail is a bit on the shy side on area.

Also with my CG I'm finding that the 5mm snap flap is way too much.

So with the passage of time have others (the British F3F team) come back with different set up values. I know a lot of this is personal preference

Next time out I'm thinking of moving the CG forward and seeing how she responds. But I do like how the Redshift holds the line in knife edge at the current CG..

Hi Konrad - TOTALLY personal. The guys who flew the Redshift at the world champs all had wildly differing setups.

I think it can be a bit like F1 racing. Even if the Team drivers are pretty much the same size, its really difficult for Team driver A to drive Team driver B's car just around a circuit. In competition its completely out of the question.

Thats why they spend so many weeks and months before the season setting up, and then days before any race doing fine tuning - and then they make last adjustments on race day because of weather/track variations. Happily, over time, the managers get to know the drivers preferences and the car's limitations and have "Crib sheets" to cover a lot of the weather, track surface and topographical variations from race site to race site, so that makes it. little easier - but apparently not much.

Then, there's the luck factor. Many an F3f race has been won by a slightly off topnotch flyer because he was lucky enough to have a thermal come through.

All in all, in F3f or in MOM for that matter it doesn't matter so much what you fly, as long as it is actually a competitive airframe - its how you fly it. My boggle is that I want to take the "so much" and make it into "very much". In other words, a clear advantage.

Problem is, designing the plane to go fast (In theory) is not enough - if only I could also design the pilot...

Doc.

 

[Konrad]

Totally understand. I'll just have to make a change and see how I like it. I'm tying to avoid the stupid stuff like wash in thermal mode!

 

[Wayne]

Tip stalls and camber settings - When I have a plane that has shown to have tip stall in thermal mode I will use very little or NO aileron camber, just use the flaps. Keep those tips clean. Do I give up performance doing this? I think there is an argument for avoiding the stall equals better performance. And as you load the plane more, or fly at sites in the mountains this gets even worse.

 

[Konrad]

To be clear my Redshift stalling in thermal mode was as a result of my improper rigging. I'm actually surprissed that I didn'd see this on Wedensday! The tip stall or the wash in. This is a good indication of sound wing design.

Yep, flying at high altitute is much like adding to the wing loading. Less air to support the same amount of weight.

 

[Konrad]

This has to be an annoying problem that designer always have to deal with. That is folks assign flight issue to the airframe when the true cause often lies somewhere else!

I just went through my programing for the RedShift and found that while I had proper differential set up for the ailerons, the same can't be said for the flaps. I have my flaps coupled to the ailerons. I have the flaps mixed in as ailerons at about 2/3 the movement of the aileron. The problem I found was that my downward going flap was actually moving more than my upward flap. This resulted in reverse aileron differential for the flaps. Just what I don't want with an airframe thought to be a bit shy on rudder area.

I'm hoping that this set up error is what was causing me to have some difficulty getting consistent placement in the turn. While I don't think this had too much effect on the straight line wiggle I noticed, I'm sure it didn't help!

While I'm sure some of my post stall flight issues can be traced to the undersized vertical area. I'm now convinced that much of my placement problems can be traced to improperly set up programing.

I really want to get back out on the slopes and test the programing prior to Sunday's race. I know, I know I'm letting racing interfere with my flight testing!

I'm off to check my other racers, after all my poor standings in the pilot rankings can't be just as a result of my poor piloting!

 

[Doc James Hammond]

"after all my poor standings in the pilot rankings can't be just as a result of my poor piloting!"

As with us all (except me) this possibility is absolutely out of the question, and should never again be written down.

Result of poor piloting? The very idea!

Doc.

 

[Konrad]

I'm starting to think I belong to the Mad Hatter's slope racing club. Race tomorrow and race yesterday but never racing today! Again last Sunday's race was canceled for lack of lift.

Well, today I got in some more flight testing. I'm slowly getting there! Today I heard the the RedShift rip on two of my passes. This is definitely different than the "normal Swish". I'm really liking the mild snap flap. (This was with no ballast) I think this was key in allowing the RedShift to get up to speed to start ripping! I still don't like the fish tailing I get with anything other than a perfect turn. I'm still working on aileron differential and rudder inputs, maybe even a mix.

Doc, I think you are on the right path with the 8% larger tail. I'm thinking of lowering the V-tail angle to get more vertical area when I flip them on my second RedShift.

P.S.
I found that the aileron wiper was too large in that it bottomed out on the inner bottom skin, limiting the upward movement of the aileron. I've trimed these with a Fein Sander, metal cuttting blade. I may have to rework the aileron linkages to get more throw. But I don't want to cut into the wing after just recently getting the model reassembled.

 

[Doc James Hammond]

Good to hear you heard the "Redshift buzz" Konrad - it means you are getting the monster up on the step.

Yep 8% larger tail is a done deal - According to some experiments done in UK that mod turns it Ito an "on rails" turning machine - but you still keep the buzz. That and a skinnier, under-mounted fuse for the MKII will make it into a completely new proposition.

Getting there.

Doc.

 

[Konrad]

As we have all been suffering through my build, I thought it might be a good idea to show what the end game is all about. I just love those long high aspect ratio wings!

Now its been close to 10 years since I last used a DSLR camera. I'm sorry to say it shows! Using some auto setting and a 200mm lens this is what I got. I'd like to thank Mehrdad Amird for actually taking the photos. Any issues with the photos are as a result of my improper set up of the camera.

I have to say I like how she looks in top view. I'm not too thrilled by the bottom with the camo tail and the red and white paneled wings.

I've now got a good roll rate. All photo flights where with close to 0.5kg of ballast. Still working with the aileron dif. and rudder mix but I'm getting there.

 

[Doc James Hammond]

As we have all been suffering through my build, I thought it might be a good idea to show what the end game is all about. I just love those long high aspect ratio wings!

Now its been close to 10 years since I last used a DSLR camera. I'm sorry to say it shows! Using some auto setting and a 200mm lens this is what I got. I'd like to thank Mehrda Amird for actually taking the photos. Any issues with the photos are as a result of my improper set up of the camera.

I have to say I like how she looks in top view. I'm not too thrilled by the bottom with the camo tail and the red and white paneled wings.

I've now got a good roll rate. All photo flights where with close to 0.5kg of ballast. Still working with the aileron dif. and rudder mix but I'm getting there.
View attachment 6734View attachment 6735View attachment 6736View attachment 6737View attachment 6738View attachment 6740View attachment 6741

Yowser!

 

[Konrad]

Just to give you an idea of just how little frontal area a modern F3F racer has. Yes, there is a Redshift in that photo!

 

[Konrad]

I just went through about 100 photos of my Redshift in the turns. It looks like all but 3 show the tail a bit high or level wether in a right of left hand turn. I think this might mean I have a bit too much rudder mix. I've taken out "5" from the mix.