What engine weights are acceptable, Highlander & Superstol?

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What engine weights are acceptable, Highlander & Superstol?

Postby oz_p » Mon Aug 31, 2020 11:35 pm

Realistically, I will probably go with a Yamaha Apex conversion. It has a lot of support and we'll see how they are working out over time as more and more people use them. If I'm not mistaken, the reduction drive is a bolt on affair and aftermarket wiring harnesses are available. Chances are, I probably can't do it for what Steve Henry can sell me one for and that's $23000.

But, I love radials!! There's a gentleman here that has a Rotec on his plane and I've got the hots for the Verner. I'm thinking that the 7u. The weight listed is 183 lbs. I think that is everything but oil. Max power is 124 BHP @ 2300 rpm, continuous power is 103 BHP @ 2000 rpm and 287 ft/lb or torque at 2200 rpm.

I don't really understand the torque vs horsepower argument but I think means that the higher the torque is relative to horsepower, the quicker it is. And this has to do with being able to swing a big prop. And this translates to very good short field capability. Is this correct?

The next engine up is the 9s. The claim is that this 238 lb (dry) engine which puts out a max HP or 158 hp and continuous of 136 has as much torque as a 180 hp Lycoming.

Here's the information if you want to read for yourself. http://scalebirds.com/about-1

Does anyone know how these stack up against the Yamaha conversions?
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Re: What engine weights are acceptable, Highlander & Superst

Postby mikepliske » Tue Sep 08, 2020 8:51 pm

I think your 183 pounder is comparable to the 912 and the Yamaha Apex...

I don't think that 238 pounder will work (but verify elsewhere) on a HL or a SS....with that engine, I think that you'd have to go to the SS XL, as it's good up to around 315 lb engines.... they first started hanging a UL520 and most lately have put the Titan 180hp engine on the SS XL....check their weights via google.

with thoughts of only a 158 max HP on the 238 pounder, if put on a SS XL....I think you'd be better off with the 183 pounder @ 124 hp on the HL or SS.

Mike
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Re: What engine weights are acceptable, Highlander & Superst

Postby BucF16 » Wed Sep 09, 2020 3:54 am

Hold on, I need to get my Popcorn.

Just kidding.......Hey Mike, I'm sure Dane will chime in. I'd call him, He'll give the Cons and Pros. I'm in FRA and do another on Saturday. I'll try to call you in-between.

Cheers
Bruce Johnson Highlander # 393
"Because I fly, I envy no man on Earth"
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http://www.bruceshighlander.blogspot.com
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Re: What engine weights are acceptable, Highlander & Superst

Postby danerazz » Wed Sep 09, 2020 10:03 am

My understanding is the Highlander was designed for a 200lb or less engine. When I started my project I spoke to Troy about the Rotec, which is supposedly 220lbs without the oil tank. Troy thought it was okay, though the extra weight was not in the spirit of the STOL ideals of the highlander. It has resulted in an 840 lb empty weight. I did have to add 5 lbs of ballast in the tail, and 10 probably would have been better.

The issue with adding 10% to the weight is you will not get quite as good of performance out of it on the same power, and CG may be tricky.

Torque lets you turn a big prop, and big props give you better climb than a small prop turning fast. You can get more power out of a small, high rev, high horsepower engine by putting a reduction drive on it to act as a torque multiplier. That lets you use the power it produces on a longer prop without the tips going supersonic.

My engine has a 3:2 reduction, so at 3600 rpm, the prop turns 2400 rpm. I am turning a 78” prop.

I had to reshape the firewall and build an appropriate boot cowl. This was not that big of a deal, paint and fabric was MUCH more of a chore than that. I also had to build my own fiberglass cowl to make the transition from round engine to less-round firewall. I hate fiberglass. I cannot stress enough how much I hate fiberglass.

My inspection is in limbo, DAR had something come up. I’m hoping for next week, but we’ll see. Hopefully I can give a flight report shortly after.

It DOES sound pretty good, though...

Would I do it again? Probably not. Reasons include questionable resale, and insurability. The project was not a problem, and I have not had any issues with the engine. I feel pretty good about accomplishing the build the way I did, and putting a VERY unique and personal touch on my plane.
Dane

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Re: What engine weights are acceptable, Highlander & Superst

Postby oldguy » Tue Sep 15, 2020 11:25 am

I am going with an Apex in my highlander
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Re: What engine weights are acceptable, Highlander & Superst

Postby BDA » Tue Sep 15, 2020 2:06 pm

Not to throw gasoline on the fire...

But I hear that there is a Titan 0-370 going on an XL at the factory!!

I would do that if I were to build again. My buddy has one in his cub, 200+ hp is fun.

On the other hand 100 # lighter with 1,000 #s thrust is very interesting...
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Re: What engine weights are acceptable, Highlander & Superst

Postby BucF16 » Tue Sep 15, 2020 7:59 pm

Oh Crap! This will be fun to see!

Cheers,
Bruce
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