Manufacturer specs? Incidence question and looking for digital trainer

P

ProtocalZ

New member
I'm having trouble maintaining level flight with all trainers at lower speeds. I looked at some major angles of Dynaflite Super Decathlon in RF8 as an example. Aircraft editor lists

  • Main Wing angle of incidence at root -2.0
  • Main Wing washout 0
  • Stab angle of incidence -1.9
Great Planes lists
  • Main Wing angle of incidence -1.9
  • Main Wing washout 2.0
  • Stab angle of incidence -3.5
Setting the model to GP results in a plane that flies level at half throttle and rises and lowers on engine power alone.

Then there is the PT-40. Manual states it should fly level with neutral elevator trim at 1/4-1/3 throttle. Not in the trainer; she dives if not >3/4 throttle. GP does not list the technical data.

Is there something I am overlooking? Don't mind learning about building an aircraft, I just want to see if Knife Edge knows something I haven't pointed out here, or if someone has a suggestion for a 4 ch trainer.
 
I've had great success editing stock planes to exactly match whatever current one I am flying. For example, taking the stock Yak, and editing it so that all dimensions, angles, airfoils, weights, etc. match my current Flex Innovations QQ Yak. And RF replicates very, very well the idiosyncrasies of the "real" model.

So, I would hazard a guess that the manufacturers of the actual models may "tweak" their production runs as they get feedback from the field - both planes noted, for example, have been around for a really long time. Likely that RF, however, does not get notified of the updates, and then differences can creep in.

I was instructing at a club this year, and the out-of-the-box club trainer they gave me to use was from 1995. Another one the club uses, with the same name, just a different color scheme, was from about 2010. Very different in CG placement, incidences, thrust angles, etc.

I did a little bit of testing of the PT-40, and the RF version is nose heavier than I would find acceptable. In the editor, try moving the CG back to about -.6 or so, rather than the default +.24 That settles down the pitch changing with speed a lot. If I was to do a bit more work with it, I would add a bit more downthrust, also. That should resolve most of the issues.
 
ProtocalZ said:
I'm having trouble maintaining level flight with all trainers at lower speeds. I looked at some major angles of Dynaflite Super Decathlon in RF8 as an example. Aircraft editor lists

  • Main Wing angle of incidence at root -2.0
  • Main Wing washout 0
  • Stab angle of incidence -1.9
Great Planes lists
  • Main Wing angle of incidence -1.9
  • Main Wing washout 2.0
  • Stab angle of incidence -3.5
Setting the model to GP results in a plane that flies level at half throttle and rises and lowers on engine power alone.

Then there is the PT-40. Manual states it should fly level with neutral elevator trim at 1/4-1/3 throttle. Not in the trainer; she dives if not >3/4 throttle. GP does not list the technical data.

Is there something I am overlooking? Don't mind learning about building an aircraft, I just want to see if Knife Edge knows something I haven't pointed out here, or if someone has a suggestion for a 4 ch trainer.
Click to expand...

On the PT-40, take the washout out of the main wing. I also modded the H-tail incidence
 

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  • PT-40 mod_AV.RFX
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Legoman's mods make it better. But it is still not a great trainer. I messed with it more, also, and it started to bring back memories of why I disliked training with this plane in the past. Once built, there's not much to do except to play with wing incidence (I used to carry popsicle sticks to help beginners shim the wing of their plane) and play with down thrust. See this thread on RCGroups about struggles with the real model:https://www.rcgroups.com/forums/showthread.php?2534887-My-plane-wants-to-climb And yes, apparently they updated specs of various aspects over the years.

For just having a GOOD plane to learn to fly with, search the swap pages for "Das Ugly Stick". I just tested this one by Technoid (https://forums.realflight.com/index.php?resources/22090) and it behaves as I think a really good trainer should. Yes, the 7.5 version is fine when using RF 8.
 
Thanks for the trainer help, especially the PT-40 which I was fond of as a kid and still think is a very sharp looking RC model. Flapper, I was going to say after your CG edit which helped a lot, I found GP's PT-40 data: wing inc 3.5, H-stab inc 2 and engine 4.5 down, 0 right. I have a lot to work with, but will be trying both the suggested planes first. I appreciate the support.
 
My goodness, that's a big Stik inside LIARS field. Do you suggest a huge plane because we'd all learn on something this big if not for real life costs and storage expenses? The other size extreme I deal with in real life. The dingus at the local shop sold me a mini-Pitts as a next plane from a three channel powered glider. Poor Pitts, I put glue on her as often as I put her in the air.
 
ProtocalZ said:
My goodness, that's a big Stik inside LIARS field. Do you suggest a huge plane because we'd all learn on something this big if not for real life costs and storage expenses? The other size extreme I deal with in real life. The dingus at the local shop sold me a mini-Pitts as a next plane from a three channel powered glider. Poor Pitts, I put glue on her as often as I put her in the air.
Click to expand...

I just picked it because it was the first Ugly Stick I ran across that was an EA (Entire Aircraft) AND because it was done by someone I know can set up an excellent plane in RF. A few test flights verified that it behaved as I would want a trainer to behave when teaching someone. Size was not really considered, since I assumed you were mainly looking for a very well setup plane to practice with. I think technoid may have some other versions out there, that are smaller.
 
I've been enjoying the big stik and have been able to move onto more squirrely models. The Kadet didn't work immediately, im sure it's another download which I'll get right now. Pleasant story: the local shop had a PT-20 so I'll have a real life trainer in a few months. With your experience flying the PT and my simulator time, could you suggest I build the plane in the low dihedral - no washout option?
 
Flapper said:
I've had great success editing stock planes to exactly match whatever current one I am flying. For example, taking the stock Yak, and editing it so that all dimensions, angles, airfoils, weights, etc. match my current Flex Innovations QQ Yak. And RF replicates very, very well the idiosyncrasies of the "real" model.

So, I would hazard a guess that the manufacturers of the actual models may "tweak" their production runs as they get feedback from the field - both planes noted, for example, have been around for a really long time. Likely that RF, however, does not get notified of the updates, and then differences can creep in.

I was instructing at a club this year, and the out-of-the-box club trainer they gave me to use was from 1995. Another one the club uses, with the same name, just a different color scheme, was from about 2010. Very different in CG placement, incidences, thrust angles, etc.

I did a little bit of testing of the PT-40, and the RF version is nose heavier than I would find acceptable. In the editor, try moving the CG back to about -.6 or so, rather than the default +.24 That settles down the pitch changing with speed a lot. If I was to do a bit more work with it, I would add a bit more downthrust, also. That should resolve most of the issues.
Click to expand...
Did you actually replicate the Flex Innovations QQ Yak 55 10e? I can’t find it any where on plane swap or anything like it? Thanks
 
Wil1 said:
Did you actually replicate the Flex Innovations QQ Yak 55 10e? I can’t find it any where on plane swap or anything like it? Thanks
Click to expand...
No - it is the big 35cc gas version that they used to sell. Still flying both (the RF version and the real model) a lot. Of course no Aura in the RF version, but it doesn't really need it in the usual ideal weather conditions that RF has. Never posted it to the swap pages. While it has the wing tips and the sharks teeth the model has (and flies like it), they aren't visible since I don't make full 3D models.
 
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