xray328

My Feedback: (1)

I flew my 2 1/2 pound SPAD today with an Enya .15, 10%, and a 7x4 prop. Man was that thing a dog. It could barely fly the plane. I think the prop is too small but I'm pretty new to glow planes. I (actually my instructor) ended up nosing it in and it broke the 7x4 and before I could try a 8x5 I found more damage that ended the day. I was using the 7x4 because thats what it came with (used) and thats what everyone said I should for a .15. The thing is though, I've heard that these Enya's really sing with a 9x6. I think people are hearing ".15" and so they automatically toss out a 7x4 recommendation. Is the Enya an exception to this rule?

piper_chuck

My Feedback: (12)

9x6 on a .15? Sounds too big. Try an 8x4, the extra inch will give more thrust than the 7x4.

xray328

My Feedback: (1)

See thats just it, people hear .15, not Enya .15. Maybe its not as big of a deal as I was lead to believe. Do you think an 8x5 is too much? Its just that I have one of those already. How do you know when you go too big?

piper_chuck

My Feedback: (12)

You could try the 8x5, but most of the answers you are getting is 8x4. See the pic on the left? It was my first plane, a long time ago. It was powered by a .15. Wanna guess what kind? See the plane on the right? While it's not powered by an Enya, it also has a .15. Both planes used 8x4 props. The advantage the 8x4 will have over the 8x5 is that it will let the engine turn higher RPMs which will probably put it in a better hp range. It's like being in a lower gear in a car, and should give you better acceleration.

jettstarblue

I'll agree with Piper Chuck here. If you are using too big a prop, the engine will have a very narrow range of tuning on the high end needle valve (one or two clicks where it will run). Plus too large a prop is hard on the engine. An Enya .15 is going to use pretty much the same prop as any .15.

ClemenTang

I settled with an APC 9x4 for my Hydeway with a Magnum .15. If your little SPAD is a draggy slow flyer you may even try 10x3 (first gear, strongest pull). The only thing that's certain is to aim for peak Hp, which is different from engine to engine and fuel/pipe combination. If you want more speed (but less pull) try a 8x5 or 8x6 (forth gear). The top rpm you're able to achieve varies for different props, even different brands for the same size due to different planform and section. Hope someone with an Enya would respond and actually recommend a size so you can work from there.

Clement

dasmiller

Okay, I knew I had an old Enya .15-IV somewhere. According to my sketchy notes, I was running an 8x6 on it, for at least a while. I've had a *lot* of planes over the years, but I really don't remember actually flying the Enya .15 in any of them, so I don't want to overstate my expertise. A 7x4 is *way* underpropped, though.

I've been running 8x5's and 9x4's on my Magnum .15XLA; I'd really recommend that you start with a prop around that size on your Enya.

Hmmm . . now that I'm looking at my engine data, I'm not sure why I'm not running an 8x4 rather than the 9x4. Static thrust is about the same (engine revs higher), and the pitch speed is higher . . . it's all good . . .

ClemenTang

Better idle with the larger prop?

Clement

dasmiller

You're giving me too much credit. I think there's a 9x4 on it because the 9x4 was handy after the previous prop (an 8x5) was destroyed when the landing gear folded during a very smooth landing. We'll have to save my opinion of the HOB Spacewalker landing gear installation for another forum. Preferably one that doesn't frown on strong language.

At any rate, the engine has only about 45 minutes of run time on it, so it's still breaking in. I'm not asking too much of the idle yet.

The plane itself weighs 33 oz wet, and the thrust/weight is very near 1, so no complaints about power with this engine/prop combination. And the plane flies great - my only gripe was that landing gear issue.