Spirit w/15 engine power pod
10-24-2005, 11:09 PM
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Spirit w/15 engine power pod
I picked up a Spirit at a swap meet and thought it would be fun to try to learn to fly a glider. The spirit has a small 15 engine that mounts on the glider with a 1 ounce tank. It gives it about 5 minutes of power to get to altitude before it goes out. My question is that the engine adds enough weight to the glider that it tip stalls extremely easily. Is there a solution other than to switch to a high start or tow? If I move the forward or backwards of the CG will it help? I could try it and see but the outcome might not be pretty. I am assuming that this is a somewhat common problem when you add a power pod to a glider.
Thanks
Thanks
10-25-2005, 02:32 AM
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RE: Spirit w/15 engine power pod
That little Pod wouldn't do anything to harm the performance of the spirit noticably for you. For a gliding expert maybe but don't fuss over it trust me! Have you weighed the entire model yet fully loaded? I'll bet a smoke that spirit weighes half the weight of my Electra and the Electra still flies amazingly well. If that thing's tip stalling there's another problem on it. Either wing incedence or something funky is going on. Is there any washout in the wingtips? At what percentage do you have the CG now? Put it in a brief dive to check if she wants to pull out by herself. If it does that means you're probably still nose heavy. Beware though! You don't want to dive it too long or you might get a flutter. I'm betting the lack of washout is the problem though.
10-25-2005, 11:33 AM
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RE: Spirit w/15 engine power pod
As far as weight is concerned, no. As mentioned check your CG and check the wing for straightness, that can make a big difference in handling.
I taught my 7 year old how to fly on a Gentle Lady which is similar in size, for which I built a new fuselage (same incidence angles and physical relationships) from light 3/16" balsa with a firewall onto which I put an OS .15, and also it had landing gear. Flew like a dream and we had many dozens of enjoyable flights, including thermalling after motor cutoff. Just had to watch speed buildup on those flimsy wings is all.
MJD
I taught my 7 year old how to fly on a Gentle Lady which is similar in size, for which I built a new fuselage (same incidence angles and physical relationships) from light 3/16" balsa with a firewall onto which I put an OS .15, and also it had landing gear. Flew like a dream and we had many dozens of enjoyable flights, including thermalling after motor cutoff. Just had to watch speed buildup on those flimsy wings is all.
MJD
10-25-2005, 11:37 AM
#4
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RE: Spirit w/15 engine power pod
The Spirit tip-stall is cured by sheeting the top of the wing tip panel back to the spar with 1/32" balsa.
But yours sounds like it has warped wings.
Spirits don't tip-stall all that easily.
A 15 should get that plane to "invisible" altitude in about 45 seconds.
Here's a .15 powered Gentle Lady, and a Spirit wing on a 64 oz .15 powered camera plane.
But yours sounds like it has warped wings.
Spirits don't tip-stall all that easily.
A 15 should get that plane to "invisible" altitude in about 45 seconds.
Here's a .15 powered Gentle Lady, and a Spirit wing on a 64 oz .15 powered camera plane.
10-25-2005, 09:51 PM
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RE: Spirit w/15 engine power pod
Thank you for the advice. Not to sound like an idiot, but what does wash out refer to? Thanks
Jeff
Jeff
ORIGINAL: Spacey
That little Pod wouldn't do anything to harm the performance of the spirit noticably for you. For a gliding expert maybe but don't fuss over it trust me! Have you weighed the entire model yet fully loaded? I'll bet a smoke that spirit weighes half the weight of my Electra and the Electra still flies amazingly well. If that thing's tip stalling there's another problem on it. Either wing incedence or something funky is going on. Is there any washout in the wingtips? At what percentage do you have the CG now? Put it in a brief dive to check if she wants to pull out by herself. If it does that means you're probably still nose heavy. Beware though! You don't want to dive it too long or you might get a flutter. I'm betting the lack of washout is the problem though.
That little Pod wouldn't do anything to harm the performance of the spirit noticably for you. For a gliding expert maybe but don't fuss over it trust me! Have you weighed the entire model yet fully loaded? I'll bet a smoke that spirit weighes half the weight of my Electra and the Electra still flies amazingly well. If that thing's tip stalling there's another problem on it. Either wing incedence or something funky is going on. Is there any washout in the wingtips? At what percentage do you have the CG now? Put it in a brief dive to check if she wants to pull out by herself. If it does that means you're probably still nose heavy. Beware though! You don't want to dive it too long or you might get a flutter. I'm betting the lack of washout is the problem though.
10-25-2005, 11:25 PM
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RE: Spirit w/15 engine power pod
Washout is twist in the wing panel.
Generally the root is flat on the table, and the -trailing edge- of the tip... or the end of the first panel out is raised above the table some slight amount...
3/16" to 1/4" would be a reasonable amount.
This can be put in, if it's not there, by heating the covering and twisting, holding the panel long enough for the covering to cool down.
The amount of washout can be checked as this is done.
Washin, OTOH, is when the traling edge at the tip/panel break is -below- the wing root. This leads to premature stalls when turning, as the tip area approaches the stalling angle before the root area.
Washout stalls the root area first, permitting the outboard sections of the wing to remain flying.
Generally the root is flat on the table, and the -trailing edge- of the tip... or the end of the first panel out is raised above the table some slight amount...
3/16" to 1/4" would be a reasonable amount.
This can be put in, if it's not there, by heating the covering and twisting, holding the panel long enough for the covering to cool down.
The amount of washout can be checked as this is done.
Washin, OTOH, is when the traling edge at the tip/panel break is -below- the wing root. This leads to premature stalls when turning, as the tip area approaches the stalling angle before the root area.
Washout stalls the root area first, permitting the outboard sections of the wing to remain flying.
