Redshift #3 (Green glass prototype)

[Konrad]

I like that you named the bench Ronaldo. I think that would be a good name for the plane.

I'd love to give her another flight should we ever be at a slope together and you happen to have her in the air. Just a couple of turns..

Are you allowed to race with a gyro?

I think you will like the improvement!

Heck, I'm happy to let you fly the whole flight.

Now about that graffiti, I had nothing to do with that! That is a new bench since I was last at Thornton Beach. It is nice to sit there and fly the bowl. But I think we will have to move a pylon a bit as it looks like it is right where we had base "A".

 

[Doc James Hammond]

Back to the Redshift in glass. I finally was able to perform a full maiden. You might recall that at the last F3F race I tried to maiden this model only to have it fall all the way down to the valley floor.

Today at Thornton Beach the wind was light but steady. I was able to fly the bowl to my heart's content. This is the second Redshift I've maiden. Again no surprises. Now I need to mention this is a glass lay up and is about 300 grams light than the maiden I had with the carbon Redshift. In the light lift the glass ship really is the better ship in that the rolls where superior. To this end I had cut down the aileron wipers to about half their as shipped size with a vibrating saw, like a Fein Sander. I'm finding that all three of my Redshifts are having the ailerons bind in the upwards direction out at the tips way before the root side binds. With the aileron tips now being able to aid in the roll the Redshift really can get up on the wing tip fast. I love it! This and the lighter weight of the wings makes the glass Redshift the aircraft I want to race in light lift.

Now the question on everybody's mind is how did the controls center. This was a major reason this model was on the shelf for 4 or 5 years. Well the model does not double center in any of the axises! I really like how nice she flies in the straights. No hunting and she is again dead quiet. The only time I could get any noise from her was in full aileron deflection. Doc. that wing really is nice to see/hear working. (I also maiden my Alpha 2.8 and you could hear the air trying to get out of the way of that ship)!

Now for the bad news. This Redshift has the stock force layout. That is the V-tail is still at 104°. With the stock V-tail it was hard to get nice pylon turns. I found that the aileron differential and rudder mix values were always changing as a function of speed. This made consistent turns all but impossible.

So while I love the wing as found on the Redshift, I actually hate how the stock Redshift carves the turns. When you get it dialed in for any one speed she is fine. But as we all know F3F racing isn't about flying at one speed rather the plane flies at a host of different speed through out the whole heat. This makes the stock Redshift a poor F3F racer. I'm looking forward to trying some new tails as the wing really is intriguing.

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I'd agree with all that Konrad - nothing we haven't already discussed actually so at least the back end is consistently bad!

But...even with the bad back (like me) its done some really good times in international competetion and actually won prizes - so I guess the wing sometimes wins over the tail feathers!

Happily I hope all the bad points are fixed on the new version, and it will be really nice.

The thing is, as a designer I NEED input like this - especially when the aircraft is possibly flown in competitions - but I rarely if ever get any constructive criticism. With the allrounders like the Corsa and the Forza - even the little Sessanta, its a lot easier as they were devloped from my previous designs and so most of the competition has actually been from models designed by me. So...thanks again for all the valuable input.

Take a look at this typical British Sunday slope - Conicidentally ALL of those models - even the ones you can't see apparently were designed by me. So its easy to compare - and believe me they do...

Cheers,

Doc.

 

[Konrad]

Thank You Doc. Yes, there is nothing new here that we haven't discussed in detail in my other Redshift thread.

Now I'm not an "A" list flier nor a "B" or "C" list flier so I'm not skilled enough to extract the optimum performance from any design. But as an engineer I can see issues in how a plane flies and have some background in what leads to these characteristics.

To that end I was surprised with my first Redshift how much the change from 104° to 99° improved the directional stability. One of the goals with this glass Redshift was to verify that the 104° V-tail really flew as I recalled, it appears that my recollection of the 104°V-tail was repeated with this plane. Now I'm sure an "A" list flier could actively manipulate the rudder to place the Redshift where he wanted it, me not so much.

Like I said this Redshift was flying well enough that I'd like to work her a bit more to extract the performance that I think I see in the wing. I'm hoping that the replacement of the Redshift's tails with the new Spada tails will solve these issues. So I'm not going to modify this fuse for a while.

Now I test flew this Redshift at the same time I test flew my Alpha 2.8 and I was pleasantly surprised at just how much faster the glass Redshift flew and turned when I was able to keep her in the compression zone. But the small tails often made this problematic. So the performance potential is there, it is just that I can't extract it.

I'm now going to finish my 2nd carbon Redshift but with even more vertical area as a result of a V-tail angle of 97° to 96°. I'm taking this in small steps (like a good engineer).

Criticism is a difficult animal to tame. The one giving it has to be careful not to make it just a bitch fest. This is why I try to show what I've done with my limited resources to correct the issue, I try to put my money/time where my mouth is. (Here with the carbon Redshifts I've added vertical area). On the other side of the issue the recipient should be open to it, and not get too defensive. With the Redshift we had a good exchange. I know I received some good insight into how to set up your Redshift design.

Back to this particular model, I was so happy to correct the many mechanical control issues, from the difficult V-tail control arms to the simple servo covers. (This model came with four X-10, changing the aileron servos to X08 made the wing a smoother looking and operating tool)!

 

[Konrad]

Looking over my radio set up and closing in on the CoG trim I notice just how light this glass ship is. The mass I measure is 2.230 kg! I also see that I'm not using near the elevator motion allotted to the elevator in the defaults given in Shellims templets. I've changed the V-tail mix so that 40% of the V-tail movement is kept for the elevator and 60% is given to the rudder. With any luck I can go down to a 30/70 mix to gain some needed rudder power to perform my pumps.

Just for reference the much repaired carbon Redshift comes in at 2.510 kg in flight trim

 

[Doc James Hammond]

I made this one for light wind experiments, Konrad.

And just to set the cat among the pigeons, I firmly believe that a bit if wing tension bend is an ADVANTAGE in turns as the wings bend then 'ping' the model out on the other side giving the speed a nice kick in the right direction.

Problem is how to prevent the wing from moving too much in torsion - which it will surely try to do.

Woo...idea...we could use light wing contructon with a nice sine wave spar!

Cheers,

Doc.

 

[Konrad]

As you know I don't think there is anything as free power. The ping comes from the slow rate of turn earlier in the turn, loading the wings. So no gain. Then there is the issues of control associated with torsion and timing the release of the ping. As a pilot I have too many other variables to try to control. I like stiff ships. With the one flying session I'm liking what I see in the light Redshift and like you I think we can credit the SWS.

 

[Doc James Hammond]

As you know I don't think there is anything as free power. The ping comes from the slow rate of turn earlier in the turn, loading the wings. So no gain. Then there is the issues of control associated with torsion and timing the release of the ping. As a pilot I have too many other variables to try to control. I like stiff ships. With the one flying session I'm liking what I see in the light Redshift and like you I think we can credit the SWS.

I'm interested to hear what other people say on this - if anything?

Logic dictates a stiff wing - just as Konrad says. But I have never been one to accept 'accepted logic'

To ping or not to ping? That is the question.

Any inputs?

Doc.

Actually this harps back to days of old, when knight were bald...etc and a holocaustic session I had on tuned pipe resonance. But that was long, long ago, on a planet far, far away...

 

[Konrad]

Just to be clear, you and I agree that the ping happens.

Even in my F3D days I avoided flexi fliers!

Now Boeing uses flexible wings, but that had more to do with cabin comfort

 

[Doc James Hammond]

Just to be clear, you and I agree that the ping happens.

Even in my F3D days I avoided flexi fliers!

Now Boeing uses flexible wings, but that had more to do with cabin comfort

Yaaahhhh...help...scream...Yes, I know what you mean about the Boeing flexible wings - though I'm not sure they'd like you to call them that. OMG...Seeing a wingtip flex up and down 3 or 4 meters when you are in a bit of mild turbulence is somewhat alarming, until of course you tell yourself that you are an aerospace engineer...

Problem is...sometimes I don't listen to myself...

Now where were we?

Oh yes...pingwings...

Doc.

 

[Konrad]

Flew at Fort Ross Ca. for the first time. Wow, now there is a landing zone! Flew the glass Redshift and was working things a bit. I found that while the Aeroic manual has us using about half the snap flap of what we would normally use, I'm finding that I'm liking the snap flap at about 4mm. This seems to give a feeling of the plane pulling through the turn rather than being pushed from behind with the elevator.

While I still can't perform the pumps (half pikes) like I want, the 40/60 elevator rudder mix was a huge improvement. She now actually kicks the tail with rudder input!

I'm finding I like the light glass lay up, particular in roll. This points to using the smallest servo out on the wing for the ailerons.

I also flew the 99° carbon Redshift. I still like how this one tracks as oppossed to how the 104° glass Redshift tracks. But as I work things out while sport flying they are both getting better. I can't wait to try the 96° tail.

 

[Doc James Hammond]

Flew at Fort Ross Ca. for the first time. Wow, now there is a landing zone! Flew the glass Redshift and was working things a bit. I found that while the Aeroic manual has us using about half the snap flap of what we would normally use, I'm finding that I'm liking the snap flap at about 4mm. This seems to give a feeling of the plane pulling through the turn rather than being pushed from behind with the elevator.

While I still can't perform the pumps (half pikes) like I want the 40/60 elevator rudder mix was a huge improvement. She now actually kicks the tail with rudder input!

I'm finding I like the light glass lay up, particular in roll. This points to using the smallest servo out on the wing for the ailerons.

I also flew the 99° carbon Redshift. I still like how this one tracks as oppossed to how the 104° glass Redshift tracks. But as I work things out while sport flying they are both getting better. I can't wait to try the 96° tail.

Good stuff.

Actually the settings in the manual are always doctored by me to 'point' the new user in the right direction rather than give a definitive angle or amount. Snap flap is probably the MOST user-defined setting so it needs to be handled with care. Less is more there.

What I really want to see is the OVERALL difference between the MKI and MKII Spada versions. I only wish I could speed things up.

Cheers, and keep the good stuff coming Konrad!

Doc.

 

[Konrad]

You and me both! Yesterday I tried to match the 104° and 99° V-tail ships as close as possible. I had 2 slugs in the belly of the 104°. I liked, a bit better, how the 99° carbon ship grooved. But the 104° glass ship still came up on to the wing tips nicer. There maybe more going on than this, but I think the lighter mass of the glass wings helps get her up into knife edge easier.

As the Spada is a bit late in coming, I'm thinking of getting one of your older 2.7m ships. I do love your wings and this one doesn't have the V-tail. (hint; it is yellow and a Frankenstein build)

Yep, too much snap flap acts more like a brake than a lift device!

 

[Doc James Hammond]

You and me both! Yesterday I tried to match the 104° and 99° V-tail ships as close as possible. I had 2 slugs in the belly of the 104°. I liked how the 99° carbon ship grooved. But the 104° glass ship still came up on to the wing tips nicer. There maybe more going on than this, but I think the lighter mass of the glass wings helps get her up into knife edge easier.

As the Spada is a bit late in coming, I'm thinking of getting one of your older 2.7m ships. I do love your wings and this one doesn't have the V-tail. (hint; it is yellow and a Frankenstein build)

Aha...the dreaded yellow peril...

Doc.

 

[Konrad]

I think I can polish her up to give off a nice brilliance. I'm told she hasn't flown.

You know with all the crap I gave you about the camo livery, the camo has grown on me! I kinda wish this one was in camo.

 

[Doc James Hammond]

I think I can polish her up to give off a nice brilliance. I'm told she hasn't flown.

You know with all the crap I gave you about the camo livery, the camo has grown on me! I kinda wish this one was in camo.

Camo? I had to send them all to Ukraine.

Target drones.

Doc.

 

[Konrad]

We agree with your support of the oppressed. My "Great Wall" glider had a color scheme of White, Red and Blue. I just couldn't bring myself to fly it, so I corrected that error!

 

[Konrad]

Trying to make a case for the ping wing. As acceleration and drag are nonlinear functions (variables) there might be a case made that transferring the high energy state early in the turn to the lower energy state coming out of the turn is a benefit.

Now you and I know, nonlinear systems are often hard to comprehend. So I’m sure this ping wing will be controversial.

 

[gp49]

Trying to make a case for the ping wing. As acceleration and drag are nonlinear functions (variables) there might be a case made that transferring the high energy state early in the turn to the lower energy state coming out of the turn is a benefit.

Now you and I know, nonlinear systems are often hard to comprehend. So I’m sure this ping wing will be controversial.

Sound to me like you guys are racing on snow skis in a slalom. Just don't hit a rut during your loading or it will take you for a ride like a few models of the skis I used to ski with in the old days..

 

[Konrad]

I’m not. I’ve hated flying flexible models.

I’m just going through this mind exercise. I’m hoping to find something I may have over looked. Like Doc said control of this kind of dynamic structure has its own set of problems. Then we have to add learning to use a ping wing.

 

[Doc James Hammond]

I’m not. I’ve hated flying flexible models.

I’m just going through this mind exercise. I’m hoping to find something I may have over looked. Like Doc said control of this kind of dynamic structure has its own set of problems. Then we have to add learning to use a ping wing.

• The wing has a slight flex.
• You go into a high-G turn.
• As the G's ease, all that compression energy you have stored in to the slightly flexible wing (and it could theoretically be considerable) has to go somewhere.
• Maybe it could be visualised a bit like a super high speed version of a bird's wings in downward motion.

Its not lift, its...PING.

Cheers,

Doc (Certified Pingon)