High Elevation Gasser

[Gatorb8]

hi folks!
I am new to gas (as in never had one) and looking to fly a 50cc + class plane at sea level in the winter and 8000' in the summer. I would really appreciate some suggestions on plane/engine combos in the 50cc + class that fly well at high elevation from folks who fly high. I really like the EF 88" yak. I want all out 3D, light wing loading, reliable, floats home if dead stick.
thanks
Gator

[jbrink]

8000 ft!!! Good luck. I fly at 5000 ft and scramble for every bit of power. The new DA 85 with the appropriately size plane from Aeroworks seems to be a combo that works well at our club. Jim

[bodywerks]

I have experience flying at 7,000 feet with a 50cc gasser, so I can tell you that you NEED not just a light wing loading, but also a light plane. For a 50cc plane, you can hover 16 pounds (this is at 7,000 feet with about 10,000 feet density altitude), but you won't be able to pull out with any kind of authority, if at all.
With any 50cc plane, equipment choice will be highly important. This means no power expander, choke servo, battshare devices, etc - just batteries, servos, and receiver. For batteries, I am talking like a single 2100 lipo and lightweight regulator, or a single 2300 A123 (better yet would be a single 1100 at only 3 ounces!), and a little 1320 lipo or A123 1100 for the ignition.
Of course, for this to work, you need a 50cc plane that balances easy without needing all your batteries hanging off the front of the engine box to balance. Otherwise, all the efforts to safe weight are a waste.
The EF Yak is awesome, but I think it comes in at around 17 pounds and needs all battery weigt forward. If I were to go that route I would definitely at least get a EScomposites carbon fiber tuned pipe to add some extra power without adding a ton of extra weight.
I think Wildhare makes a few 50cc planes that finish out under 16 pounds pretty easily, and 3Dhobbyshop has a pretty sweet-looking(and reports say it flies better than it looks) 300SHP that has tons of wing area, is light, and balances easily with a 50.
Another option is to go with the EF Yak that you like and put a little more motor on it. I think Brilleli makes an engine in the 60cc range that is pretty light, for example.

[ben_beyer]

I'd do what Jim said or try the EF Yak with a BME 58 on an ES Composites tuned pipe.

[TimDavie]

You will need to agressively lean when going from C-level to 8,000 feet + it will be like tacking 20lbs on to your airplane.
I went from 700 ft. to 7,000 (Greeley Co.) and I was so rich it was pathetic before I leaned.

[Gatorb8]

Thanks for the suggestions, I have some research to do...
I'll come back when I've narrowed it down.

more suggestions welcome!
Gator

maybe I should stick to nitro-profiles at high elevation and keep to a basic sea level gasser for my first plane.....then advance from there, seems like price may shoot up on the high elevation gasser specs...

[ben_beyer]

Might look into doing some e-conversions if they're 40 and 60 sized glow planes. Then, all you'll need to do is find the right prop to get close to the same performance you have around sea level.

[Mithrandir]

electric motors do not suffer from altitude sickness... simply reprop to the appropriate current.... The 3W "FUN" series of planes in the 2 meter'ish size would likely be a good 10S setup with a Hacker C50..
Also... conside converting to alcohol and double your fuel tank size.

I flew my Compy Super Extra at the Big Bear Airshow in 2007... something like 6750 feet altitude.... with a DA150, it hovered at about 85% power as compared to about 65% power at 3000 feet where I usually fly....

[BTerry]

Gatorb8, I know you said you like the EF Yak (Who doesn't!!?), and I don't know if you have your mind set on a Yak, but you also might like to take a look at the 3dHobby Shop Extra 300SHP: http://www.3dhobbyshop.com/detail.aspx?ID=2281 . It is the same size (wingspan and fuse length) but weighs around 15# 8 oz if kept simple, and was designed by a high-altitude pilot (IIRC around 6400'). They have a new Slick 540 coming out that looks fantastic as well.

That said, all the statements about needing a lighter plane are accurate. Lightness rules at altitude! Having a relatively streamlined plane helps too. In the summer at 8000' you can easily approach 11,000' density altitude or greater if the weather is hot. I used to fly between two fields at 4300' and 6200', and on a hot day the higher field could be a challenge - the plane needs more speed to fly and at the same time the engine is less powerful.

[BTerry]

One more place you could save weight is to use the new BME 58cc engine, it is lighter than all of the 50cc-class engines (lighter than some 40cc). That said, a plane might be hard to balance with an engine that light.

[Gatorb8]

	Quote: Originally Posted by BTerry
	Gatorb8, I know you said you like the EF Yak (Who doesn't!!?), and I don't know if you have your mind set on a Yak, but you also might like to take a look at the 3dHobby Shop Extra 300SHP: http://www.3dhobbyshop.com/detail.aspx?ID=2281 . It is the same size (wingspan and fuse length) but weighs around 15# 8 oz if kept simple, and was designed by a high-altitude pilot (IIRC around 6400'). They have a new Slick 540 coming out that looks fantastic as well. That said, all the statements about needing a lighter plane are accurate. Lightness rules at altitude! Having a relatively streamlined plane helps too. In the summer at 8000' you can easily approach 11,000' density altitude or greater if the weather is hot. I used to fly between two fields at 4300' and 6200', and on a hot day the higher field could be a challenge - the plane needs more speed to fly and at the same time the engine is less powerful.

Looked at the 3DH 300SHP, looks nice, will have to read what the threads say.
I flew all summer at 8000' so I am familiar how things change. Have a 5.5lb profile that would bearly pull out of hover with ys63 (screams at sea level). I stuck a Saito 115 on it and that did the trick. Was heavier and had to come in hotter but had fun. I also flew a foamy daily in the yard (no loss of power there). I've been flying less than a year and am on a steep learning curve!

Like I said, I want to build my first gasser and was hoping experience from the forum would help me understand what's important and what planes have worked best. So for I have some great suggestions to look into
thanks, keep them comming!
Gator

so important factors:
Light plane (high power to weight)
Low wing loading
streamlined? not sure how to determine that?

[Gatorb8]

	Quote: Originally Posted by bodywerks
	I have experience flying at 7,000 feet with a 50cc gasser, so I can tell you that you NEED not just a light wing loading, but also a light plane. For a 50cc plane, you can hover 16 pounds (this is at 7,000 feet with about 10,000 feet density altitude), but you won't be able to pull out with any kind of authority, if at all. With any 50cc plane, equipment choice will be highly important. This means no power expander, choke servo, battshare devices, etc - just batteries, servos, and receiver. For batteries, I am talking like a single 2100 lipo and lightweight regulator, or a single 2300 A123 (better yet would be a single 1100 at only 3 ounces!), and a little 1320 lipo or A123 1100 for the ignition. Of course, for this to work, you need a 50cc plane that balances easy without needing all your batteries hanging off the front of the engine box to balance. Otherwise, all the efforts to safe weight are a waste. The EF Yak is awesome, but I think it comes in at around 17 pounds and needs all battery weigt forward. If I were to go that route I would definitely at least get a EScomposites carbon fiber tuned pipe to add some extra power without adding a ton of extra weight. I think Wildhare makes a few 50cc planes that finish out under 16 pounds pretty easily, and 3Dhobbyshop has a pretty sweet-looking(and reports say it flies better than it looks) 300SHP that has tons of wing area, is light, and balances easily with a 50. Another option is to go with the EF Yak that you like and put a little more motor on it. I think Brilleli makes an engine in the 60cc range that is pretty light, for example.

I tried to google Brilleli and all I get is forums, who sells it?
thx
Gator

[Greyhoundman]

Brilleli has gone out of business.

[Norman Soto]

Just my 10 cents.
I fly around 8600 ft.
If you want to have plenty of power, the DA 85 or bigger will do the trick (I had a H9 35% with an 85cc pulling the airframe out of hover with ease).
If you really want to stick to the 50cc class then you'll have to think of a 15 pound or lighter plane.
My first gasser was a CA Model 27% with a DA 50 in the front. 14.5 pounds empty. It had plenty (but no brutal) power to come out of a hover on a Bolly 27x10. H9 Extra 27% is light enough too, but not plenty of wing area. A bit of wing rocking there.