Trainer mods?
10-28-2004 | 04:38 PM
#1
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From: Gilroy,
CA
Trainer mods?
Hey guys,
I'm looking at spicing up my trainer (H9 arrow). It rolls really slow, too slow. I have doubled the throws on all surfaces. What else can I do to make it a little more nimble? Move the CG back? If so how much?
The wing doesn't have much dihedral, maybe 1", so I don't think that removing it will buy me anything. I'm also considering changing over to wing bolts instead of rubber bands.
Any input would be appreciated,
Chris
I'm looking at spicing up my trainer (H9 arrow). It rolls really slow, too slow. I have doubled the throws on all surfaces. What else can I do to make it a little more nimble? Move the CG back? If so how much?
The wing doesn't have much dihedral, maybe 1", so I don't think that removing it will buy me anything. I'm also considering changing over to wing bolts instead of rubber bands.
Any input would be appreciated,
Chris
10-28-2004 | 04:46 PM
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From: Wolfforth TX
RE: Trainer mods?
Seal the gaps between the aileron, and the wing that should help quite a bit.
just use what ever covering is on the wing flex the aileron up and iron a strip fo coverng just on the bottom of both wings panels and that should do the trick for ya.
Don//
just use what ever covering is on the wing flex the aileron up and iron a strip fo coverng just on the bottom of both wings panels and that should do the trick for ya.
Don//
10-28-2004 | 05:23 PM
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From: Fort Mohave,
AZ
RE: Trainer mods?
Moving the CG back will help.. I just added stick on weights 1/4oz
at a time untill it got harder to land on my Avistar.. I then added
a little more till I had to fly it to land.. They do get touchy so go
slow if you choose this option.. If your good at wood work you
could take out your wings dihedral.. But that may be going to far
as with other mods for a trainer.. It may be best to just move up
to a better model.. There's a few options that will make it fly some
what better.. But trainers can really only go so far... Best to leave
as is and move up.. Save the trainer to maybe teach a family
member or friends...
at a time untill it got harder to land on my Avistar.. I then added
a little more till I had to fly it to land.. They do get touchy so go
slow if you choose this option.. If your good at wood work you
could take out your wings dihedral.. But that may be going to far
as with other mods for a trainer.. It may be best to just move up
to a better model.. There's a few options that will make it fly some
what better.. But trainers can really only go so far... Best to leave
as is and move up.. Save the trainer to maybe teach a family
member or friends...
10-28-2004 | 05:59 PM
#6
Senior Member
RE: Trainer mods?
Do the whole bag of tricks -- it's worth it as an exercise & the plane will fly beautifully.
Remove the dihedral -- it WILL have an effect. Also drop the wings into the fuselage by ~ 3/4 " -- this will move the center of lift closer to the thrust line.
Convert to a taildragger -- less weight & drag, plus you will learn how to fly a taildragger
Convert to bolt-on wings -- less drag & good construction practice.
Remove 1/2 down thrust & all right thrust -- you won't need it & it costs performance.
Add POWER
Have fun -- this is a really worthwhile exercise & the plane will be a delight to fly, plus YOU did it, not the ARF man.
Remove the dihedral -- it WILL have an effect. Also drop the wings into the fuselage by ~ 3/4 " -- this will move the center of lift closer to the thrust line.
Convert to a taildragger -- less weight & drag, plus you will learn how to fly a taildragger
Convert to bolt-on wings -- less drag & good construction practice.
Remove 1/2 down thrust & all right thrust -- you won't need it & it costs performance.
Add POWER
Have fun -- this is a really worthwhile exercise & the plane will be a delight to fly, plus YOU did it, not the ARF man.
10-28-2004 | 10:06 PM
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From: Gilroy,
CA
RE: Trainer mods?
Actually, that's what I did. I setup the dual rates on my 7C so that the low rates are stock, and the high rates are at max throw. I also setup the high rates so that they have around 50% expo so that the center of the sticks feels like the low rates.
Chris
Chris
ORIGINAL: kokamo
maybe.....just maybe, get a TX that has dual rates and put the high rates to the max and that autta get er tumblin' along
[8D]
maybe.....just maybe, get a TX that has dual rates and put the high rates to the max and that autta get er tumblin' along
[8D]
10-28-2004 | 10:12 PM
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From: Gilroy,
CA
RE: Trainer mods?
Well, I have a Super Sportster that someone gave me. It's not quite ready, so I thought I'd do what I can in the next couple nights. I probably only have an hour or two do do my mods. Modifying the wing is out. I already have a taildragger, so I think I'll skip that. I can probably do the wing bolts. On my Arrow the motor has very little, if any right thrust, but the entire firewall has about 5-10 degrees of down thrust. I could probably shim the motor mount to remove some of it. I might give that a try. Why would it have so much downthrust? Doesn't 5-10 degrees sound excessive?
Thanks,
Chris
Thanks,
Chris
ORIGINAL: britbrat
Do the whole bag of tricks -- it's worth it as an exercise & the plane will fly beautifully.
Remove the dihedral -- it WILL have an effect. Also drop the wings into the fuselage by ~ 3/4 " -- this will move the center of lift closer to the thrust line.
Convert to a taildragger -- less weight & drag, plus you will learn how to fly a taildragger
Convert to bolt-on wings -- less drag & good construction practice.
Remove 1/2 down thrust & all right thrust -- you won't need it & it costs performance.
Add POWER
Have fun -- this is a really worthwhile exercise & the plane will be a delight to fly, plus YOU did it, not the ARF man.
Do the whole bag of tricks -- it's worth it as an exercise & the plane will fly beautifully.
Remove the dihedral -- it WILL have an effect. Also drop the wings into the fuselage by ~ 3/4 " -- this will move the center of lift closer to the thrust line.
Convert to a taildragger -- less weight & drag, plus you will learn how to fly a taildragger
Convert to bolt-on wings -- less drag & good construction practice.
Remove 1/2 down thrust & all right thrust -- you won't need it & it costs performance.
Add POWER
Have fun -- this is a really worthwhile exercise & the plane will be a delight to fly, plus YOU did it, not the ARF man.
10-28-2004 | 10:32 PM
#9
Senior Member
RE: Trainer mods?
If it has a flat bottom wing, differential ailerons will give it better response. That's where the ailerons go up about twice as much as they go down. Does it have one servo under the wing?
10-29-2004 | 08:41 AM
#10
Senior Member
RE: Trainer mods?
Down thrust is used to counter the offset drag of a wing that is mounted well above the thrust line. Dihedral increases that offset.
If you are not going to remove dihedral & lower the wing, I suggest that you add a bit of negative incidence to the wing -- start with a 1/8" shim under the trailing edge & go from there. You will need to reduce the down thrust if you do that, & you may have to trim in a bit of up-elevator. Your inverted flight will improve noticeably. I have found that as much as 1/4" of neg incidence works reasonably well on most standard trainer types, without introducing serious negative effects.
If you are not going to remove dihedral & lower the wing, I suggest that you add a bit of negative incidence to the wing -- start with a 1/8" shim under the trailing edge & go from there. You will need to reduce the down thrust if you do that, & you may have to trim in a bit of up-elevator. Your inverted flight will improve noticeably. I have found that as much as 1/4" of neg incidence works reasonably well on most standard trainer types, without introducing serious negative effects.
