F22 First EPP Foamie

[BTCat]

Apr 1, 2010 18:24:17 GMT -6 akent said:

That was BT that wrote that, 19k!

But I believe it. Hot melt is flexible, too. I don't know how flexible compared to Welders, though.

I saw it earlier, but I wasn't going to say anything. Kent is much smarter than me. Nice to be confused with someone like that

[19000rpm]

Apr 1, 2010 20:08:59 GMT -6 BTCat said:

Apr 1, 2010 18:24:17 GMT -6 akent said:

That was BT that wrote that, 19k!

But I believe it. Hot melt is flexible, too. I don't know how flexible compared to Welders, though.

I saw it earlier, but I wasn't going to say anything. Kent is much smarter than me. Nice to be confused with someone like that

Sorry BT somehow I missed your post and saw Kent's reference to it.

If I'd had a nano second to shut the motor down I would have. LOL ;D

I think a raised motor mount, like the stryker, might work if you could get the plane rigid enough. Right now I think the plane is too flexible and the off center thrust might bend the foam and angle the motor. That's just a guess.

I'm going to try a sport prop on it because that's the only thing they have over at HZ right now.

Of course, now the wind and rain thing is starting up again. We broke a 132 yr record for NO SNOW in March. Somehow we'll be paying for that.

[19000rpm]

It's still a little nose heavy. I flew it for a battery with about 12 clicks of up elevator and it still required holding the stick in a slightly "up" position to keep if flying straight.

I've moved the battery about a half an inch back for the next flight.

I'm also going to add a couple of 2mm tubes of CF on top of the wing to, hopefully, eliminate the flexing there. I think the flexing may be slowing it down some. I'm guessing maybe 70mph, tops, right now. I'm using a 6X4 sport prop. It doesn't have any flex in it like the electrics. Seems to work good.

I flew it at varying throttle settings and landed it about every minute, to a minute and a half, to check to see how she was holding up.

I don't think the 1000mAh is good for more than 4mins flying the way I have so far.

After 6 landings, including the hard landing last week, the whole plane looks very solid . Elevons are staying attached along with all the bits and pieces...At least for now. ;D

[akent]

That's awesome, 19k!!

I'm glad you were able to build yours strong up front.

My guess is that you are at least twice as fast as mine. I really think mine hits 30-40mph! Into a 20mph or so wind, it is probably 10-20mph!

I'm ready to add ailerons to mine. They might be too much for your speed demon, though. Mine just has too slow of a roll rate, and I have the throws pretty much maxed out. It loops just fine. Just the roll rate is slow.

Have you tried any high alpha with yours, yet? Oh, and if a 1000ma battery flies like that, I wonder how a 1300+ battery would be to give you more speed...
Kent

[19000rpm]

I tried some high alpha, but with the nose still being heavy it didn't work that well so I didn't spend any time with it yet.

I accidentally had it on low rates the first part of the flight. Once I got it on high rates it was better, but still a little sluggish on the roll. There seems to be plenty throw on the elevon, but maybe it needs to be larger or maybe it's flexing some even with the CF I added.

The 1000 is a 25C. I don't have any 25C 1300's and I think you are right; that might give it even more speed with a little longer flight times

[19000rpm]

Gusty day for more testing, but what the hey? ;D

Well anyway, I decided to wring out the F22 a little more today to see if the CG was better if I found out nothing else. I had moved the battery back a little more. I'm getting closer. It's much better. I need to move it back even more for the next test.

I had added some CF to the top of the wing running parallel to the wing sweep from the fuse past the prop hole which did help the airframe stiffness.


I did some high speed passes and I'm starting to really believe this is a 70 mph bird.

The high Alpha was better too although the gusting winds made it hard to tell what was really going on.

Like Kent, I find the roll rate to be less than spectacular. I'm not sure if I'm going to work on this just yet. I need to fly this thing in less wind and gusting first.

[akent]

Is that black EPP now? It looks great!

That's awesome about yours flying 70!
Your extra CF on top is very similar to mine, but I went farther forward. Mine was flexing forward of the fuselage/wing joint.

I think I'm ready to try again. I have scrapped my Grayson version, pulling out all of the CF. I did buy some more 1.9# EPP, so I think I'll build another one, and see how that foam compares. It feels about the same though, just by touchy feely.

So, I will put the Grayson motor back into a new one.

Oh, one thing I did is use poster board for the templates. I cut out the plans on paper, used 3m 77 on them to stick them to poster board. I then cut the poster board out. I have already used these on two planes and they are perfect!
So, if you think you might want to build more of something, this works great.

Best,
Kent

[19000rpm]

Apr 7, 2010 18:52:37 GMT -6 akent said:

Is that black EPP now? It looks great!

That's awesome about yours flying 70!
Your extra CF on top is very similar to mine, but I went farther forward. Mine was flexing forward of the fuselage/wing joint.

I think I'm ready to try again. I have scrapped my Grayson version, pulling out all of the CF. I did buy some more 1.9# EPP, so I think I'll build another one, and see how that foam compares. It feels about the same though, just by touchy feely.

So, I will put the Grayson motor back into a new one.

Oh, one thing I did is use poster board for the templates. I cut out the plans on paper, used 3m 77 on them to stick them to poster board. I then cut the poster board out. I have already used these on two planes and they are perfect!
So, if you think you might want to build more of something, this works great.

Best,
Kent

I'm not sure of the speed because I've never flown it on a low wind day. For now I'll "believe" it is around 70. ;D

That is actually the original blue paint. I don't know why it looks black. Must be scortch marks from all that speed. ;D

I like your idea for a pattern. I'll do that.

I also noted your CF on the top of the wing. I sat there and bent the airframe a dozen times trying to figure out where I could add the least amount of CF for the best result. That seemed to be the best spot. It cut the flexing in that area by at least 50%, maybe more.

There are so many places that could use a little reinforcing, but you have to stop somewhere...I guess. ;D

I moved the battery back even more. The CG in now located right on the edge of the motor mount. I'm thinking that this might be the ideal spot with the 1000mAh battery for both speed and good high alpha.

Now, if the wind would give me a break maybe I'll be able to see what it's really capable of.

[Gabe]

Guys, this thread is amazing. I finally read through the whole thing without just glancing at each post. I think I'm down to build an F-22. It sounds like you are having too much fun!

19000, which motor are you running? I was thinking about beefing it up to the Mega Jet motor at Grayson, but the bigger battery scares me with the COG.

[19000rpm]

Apr 9, 2010 8:15:26 GMT -6 Gabe said:

Guys, this thread is amazing. I finally read through the whole thing. I think I'm down to build an F-22. It sounds like you are having too much fun!

19000, which motor are you running? I was thinking about beefing it up to the Mega Jet motor at Grayson, but the bigger battery scares me with the COG.

I'm using the Grayson V2 motor. I think the airframe would need even more stiffening for the mega jet. But, it would be insanely fast for non glassed over EPP.

I think you could get a good CG. The battery would probably be fairly close to the the motor.

I haven't had a chance to try my new CG yet. Probably tomorrow. If that goes well I may try the 1300 battery.

[Gabe]

Did you do the KF spoiler mods or the aileron mods?

[19000rpm]

Apr 10, 2010 8:38:26 GMT -6 Gabe said:

Did you do the KF spoiler mods or the aileron mods?

I stiffened the elevons with CF (see pics) but I didn't add to the elevons because the EPP is just too soft without adding more CF. Depending on the elevon adjustments I make from here on out; I might make the elevons larger and even of a different material if I build another one.

Sat. AM flight report: Winds were low, 4-8 mph. I used the 1000mAh 25C battery moved slightly back from the last flight. The CG was right on the motor mount. I flew 2 packs.

The elevons still have about 10 clicks of "up" Tx trim.

It flew much better. Much less of a tendency to nose down, but still a little.

Now, I'm thinking the top end is more like 65 mph. Maybe 70 down wind.

I spent a little time with high Alpha and low speed flight. Looking good with room for improvement.

Next Steps: Getting the nose nuetral; I think that some of the nose down attitude is either the back half flexing or the thrust angle is off slightly. I don't think the nose attitude is entirely about the CG, but I'm moving the battery back even more to try to compensate.

Increased elevon throw: She's still a little slow to respond on turns, loops and rolls. I had the control rods on the outer most hole of the control horns. It "looked" like plenty of throw. I moved the rods in to the second hole. We'll see how that goes.

[Gabe]

Let us know how those improvements work 19k. I'm really interested in building one of these.

[19000rpm]

Apr 10, 2010 17:34:42 GMT -6 Gabe said:

Let us know how those improvements work 19k. I'm really interested in building one of these.

I flew the F22 with the elevon control rod position changed and the battery moved farther back.

The nose was a bit more neutral but still not able to maintain level flight without up elevator.

Loops were much tighter and rolls a little faster, so changing the elevon control rod position has improved the aerobatic capabilities and moving the battery back has helped. High Alpha is much better. A decent cobra.

Next Steps: Moving the battery back even further and putting the control rods in the innermost holes on the elevon horns.

Analysis: The small changes I've made after each test have improved overall performance, with the exception of speed. I believe the flexing in the wing is probably slowing the plane down some and inhibiting both level flight and aerobatics. I'm going to tackle additional stiffening after the next test flight. This plane would do 3D much better with rudders. HMMMMMMMMMMMMMMM.... ;D No, I'm not going to do that.

Overdue: Special thanks to Kent for introducing this plane to me and all of his help. Thanks to BT and Gabe for your support.

[Gabe]

In case you get a wild hare (or is it hair?), here is the link to the KF and rudder mod for the F-22:

www.rcpowers.com/f-22/F-22_MOD.pdf