beavertail

What would you power a 1/4 scale Cap/Edge/Extra with if you wanted it to be realistic. I read that a Extra 300 has around 300 HP. How much do these aircraft weigh.
Any info is appreciated.

jrf

My Feedback: (551)

The full scale aerobats do not have unlimited verticle. A 1.20 fs in a 73" (12 lb.) model or a 1.80 fs in an 80" (15 lb.) would be pretty realistic. You'd have to run a 6 pitch prop on either of them.

Jim

beavertail

Hey,, Thanks for responding. ANy idea on how much they weigh, Im researching that right now.

Flyfalcons

Gross weight on the Extra 300 is 2,095 pounds. They weigh 1,440 pounds empty.

www.extraflugzeugbau.com

beavertail

FlyFalcons, Thanks alot for the info, and the website, Thats what I needed.

Joey

jrf

My Feedback: (551)

I'd be curious to hear what your research tells you about that question.

Jim

beavertail

I got roughly 1 HP per 7 pounds of plane. I dont think that is entirely accurate, But close. Im sure im leaving out alot of other factors. I just wanted an idea for my Vector flight Extra 300s.
Any suggestions on this.

Flyfalcons

That sounds pretty close; I've heard 1 to 6.7 so its somewhere around there. Remember, when they compete they aren't at gross weight, so you have to add the weight of a pilot and 30 minutes of gas to the empty weight of the plane.

Scale performance with an IMAC plane isn't as impressive as scale performance with the real thing because the real thing can attain speeds that allow very tall verticals.

beavertail

Actually, 6.7 is what I got also, What would you power a 7 pound plane with to get a close to the performance of a Full scale Extra.

Flyfalcons

Probably a 65 or so would give scale performance. That will give you nice verticals without having to dive to get the speed.

Silvanskii

My Feedback: (17)

Just remember you would have to use a flat pitch prop. And since we don't have adjustable pitch props yet, you could dive for speed at WOT as much as you want but you won't get very fast. Certainly not fast enough to be very scale, and probably not fast enough to do hardly any vertical maneuvers at all.

jrf

My Feedback: (551)

A 7 pound 1/4 scale aerobat? I'd sure love to find one of those!
But ignoring that problem for a moment, and using your pounds per hp guideline of 6.7 to one, a 7 pound airplane would require a .40 two stroke or a .52 four stroke.

Doesn't sound like that ratio will work too well for a model.

Jim

beavertail

THe 1/4 scale was just for comparison.
Sorry for the confusion.

Common sense applies.

I agree that a 40 or 52 wouldnt power adequately, I guess you cant directly compare a model with full scale.

Thanks for posting