Powersport Aviation

[cjensen]

I met with Jim and Jerry from Napa, CA at OSH last week to talk about their installations. Also had several email corespondence with Ray at Powersport in the last couple of days, and I have to say that I am impressed with the engine and installation-especially as a firewall forward kit. Prices are comparable to the Lycosaur/Lyclone prices when new or remanufactured prices are considered.

They need a few orders to get things going again, but are on the path to producing the engine kit again. Currently producing and shipping PSRU's and exhaust systems.

I am definately considering this an option for my -7 with a rotary. I will still put a fixed pitch prop on the front as the electric MT C/S is mucho dinero $$$, and I just can't see adding that much to the price of the firewall forward. Plus, the performance numbers don't add up to be much better than the FP.

Anybody have any thoughts on these guys?
Did anyone else meet them at OSH? I know Ray was there, but no booth.

[rv6ejguy]

I'm pretty much up on all alternative engine packages out there. I think these guys have by far the best engineered rotary on around. Real engineering and testing went into the redrive. Machining and installation details look top notch and very well thought out. I like their proper solution to rad layout and cooling with the new cowling, which looks mean and they are the only ones out there to have the guts/ confidence to fly to Van's to test head to head against Van's demonstrators. That says a lot. I think these guys have done it right and the price looks reasonable for what you are getting.

[rv8ch]

I enjoyed looking at these planes at Oshkosh. The two builders were very generous with their time.

You mentioned performance numbers on the variable vs. constant speed prop. Were these tests run on an auto conversion?

I would reconsider the fixed pitch prop. The range of RPMs you can fly with a typical auto conversion really cries out for a constant speed prop.

[Rotary10-RV]

Originally Posted by rv6ejguy

I'm pretty much up on all alternative engine packages out there. I think these guys have by far the best engineered rotary on around. Real engineering and testing went into the redrive. Machining and installation details look top notch and very well thought out. I like their proper solution to rad layout and cooling with the new cowling, which looks mean and they are the only ones out there to have the guts/ confidence to fly to Van's to test head to head against Van's demonstrators. That says a lot. I think these guys have done it right and the price looks reasonable for what you are getting.

These guys have a very nice engine package. They have some money problems right now. Their cooling solution is clunky and somewhat marginal. A very large rad relying on pressuring the cowl. Not as good a system as direct ducting. I have spoken to Steven Weinzerl the engineer who did the PSRU, a very intelligent guy. Powersport builds a dry sump that was sold through Mazda Speed, another nice unit though pricy. The engine and PSRU is very nice. Perhaps an escrow account for buyer protection? They need to do a better job on the rad, otherwise top notch.
Bill Jepson

[rv6ejguy]

Originally Posted by rv8ch

I enjoyed looking at these planes at Oshkosh. The two builders were very generous with their time.

You mentioned performance numbers on the variable vs. constant speed prop. Were these tests run on an auto conversion?

I would reconsider the fixed pitch prop. The range of RPMs you can fly with a typical auto conversion really cries out for a constant speed prop.

I would agree that a variable pitch or C/S prop is required for most atmo auto conversions otherwise takeoff and climb performance would be kinda poor. You just don't make much power at 4K on a Wankel in the ground roll.

The rad layout on these involves a big aluminum rad mounted just off the firewall. There is a top cowling off photo here: http://groups.yahoo.com/group/E-SubieForum/

Not elegant but I bet ground and climb cooling is no problem. Agreed that there are probably lower drag solutions but nobody is flying one ...yet.

[gmcjetpilot]

Here is the RVator article on the two nice RV8's tested against Van's demo planes. (Why the 200hp was slower than the 180hp RV I don't know, no explanation was offered in the article, except I would guess it is tired from several thousand Demo flights.) Click to enlarge, click again to enlarge more



I think the rotary is one of the best alternatives, and the Powersport is one of the nicest looking engine kits I have ever seen, regardless of power plant. I am in the Lycoming camp, but appreciate the rotary. My family had a Mazda RX3 when I was in High School. Later I bought a tired old Mazda RX2 beater to abuse, drove it, sold it for parts. The RV3 suffered the dreaded overheat that melted case seals they where known for in the early days. They have improved greatly since than, but you still don't want to overheat them.

A hydraulic prop on the rotary would be great. I am not a fan of $10,000 electric MT prop. The noise and especially the fuel burn will be harder to solve. The fuel burn is due to the inherent basic design of the Wankel combustion chamber. The use of a turbo charger can improve the fuel burn (MPG) if you fly real high (mid-hi teens) all the time (ie, O2 sucking), but that is not how I fly or use my RV, which is 80% local or short X-C. A turbo is not for me. As far as noise I read a forum post that the turbo cuts some of the noise a bit, but I still don't think stealth is the rotary long suit.

A turn off for me is the use of oil. You have to fill an oil injector every gas fill-up or add it to the gas, like a two stroke. Oil consumption on a healthy Lyc is about 1qt in every 16 hours flight, so you might get by with breaking out the oil once between oil changes.

The last is turn off is cost. If you go with a Powersport it will cost more than say a $19,000 new 180hp Lyc clone. All the alternative engine kits cost more than a Lycoming. However Tracy Crook @ RWS offers bits and pieces for a do-it-your-self rotary. With Tracy's parts and a used Mazda engine and home-grown rebuild, you can get under say 13K. It has been done many times by builders with fairly good results, but don't think it is as refined as the Powersport in looks or performance. However add an expensive MT prop you are at or more than a Lycoming. No offense to Tracy but the Powersport is a better set-up, but it cost way more. With Tracy you are left to make, design, fab and install many details, but there is nothing wrong with that. The powersport is more of a fully engineered package.

Still it cost more than a Lycoming clone and is only a few MPH faster at greater fuel burn (up to 35% more fuel burn!). With national 100LL around $3.23 that could be significant over time. So cheap rebuild or not, it is something to consider. A Lyc will give you say 2000 hours of flying before rebuild. That is how many years?

Powersport has been around forever developing their engine and reduction drive. It was started by the late RV'er Everett Hatch, who pioneered the rotary engine in RV's. Unfortunately he was killed in an untimely RV3 crash, possibly from pilot incapacitation. The work he started is continued by Powersport. I would love to see them succeed. So all you pony up and buy those power sports.

Cheers George

[cjensen]

George,

Thanks so much for the very nice write up! That's exactly what I was looking for-information, not an argument! Very much appreciated! I do have the RVator article, and read it with great anticipation and interest. I met Tracy at OSH this year, and a local friend of mine is going that route. That's probably the route I'll take as well, because it will ultimately come down to money. But, if something changes in the next year or two financially, Powersport will hear me knocking!

I am planning on using a fixed pitch prop on either engine. I have read several articles that INDICATE that the performance gain is not that great with the C/S prop-maybe I'm wrong, but a Catto three blade should give me some really great numbers. I know that take off performance will suffer a little, and climbing at 2000fpm vs. 2500fpm isn't that big of a deal for me. $10-12k for the electric prop is ridiculous.

I talked with Dave Atkins at OSH, and his oil use is no where near that high. Probably varies with each installation/engine condition/type of oil injection used. Fuel burn...well I can't argue there, but I will be able to use 93 octane as well, so there's some cost saving opportunities there. 100LL at my airport is $3.76/gal!!!!

Thanks again!

[rv6ejguy]

The oil issue is no big deal in the Wankel. Just add your oil prior to fueling. No different than using TCP in a Sube or Lycoming. Just don't forget! (Add to preflight checklist). It's a pretty good Lyc that only burns 1 qt. every 16 hours. The ones I fly are more in the 4-8 hours per qt. The Wankels I have worked use nowhere near this amount of oil.

As discussed previously, Crook and others are reporting fuel flows pretty close to Lycs when aggressively leaned using his ECUs. Crook appears to be a straight shooter but it would be best to verify these claims with a head to head at Van's under controlled conditions.

Using auto fuel can save a lot of $ if it's available at the airport or if you are willing to haul it. I can't be bothered myself but for others, it's no big deal.

I'm not keen on a $10,000 prop either but a fixed pitch prop on most auto conversions results in a serious degradation of takeoff and to a lesser degree, climb performance. You just don't develop much thrust with a Wankel at 4000 rpm with the blades mostly stalled on takeoff. With a high enough power to weight ratio, this may be acceptable to some however. This is the reality of working with the smaller engine displacements of most auto engines.

Noise is a BIG issue with the Wankel and much research is ongoing on muffler designs to take the acoustical and temperature punishments dished out by these engines. This is a weight, space and maintenance consideration. Turbos quiet these engines WAY down and solve the fixed pitch dilema but at higher cost, weight, complexity.

[cjensen]

I had always heard and read that these are turning more like 6000 rpm for takeoff, turning the FP prop at around 2600 rpm. Takeoff performance shouldn't suffer at that point, correct?

On one of the Rotary lists this morning, Tracy said he averaged 6 gph for his entire trip to OSH and back! 17.1 hours and 101 gallons of fuel. Pretty good if you ask me!

[rv6ejguy]

Not possible to have 6000 on takeoff with a fixed pitch prop and have much less than 7000-8000 in cruise flight. To have 6000 in cruise, I'd guess that you'd be closer to 4000-4500 rpm static on the ground at WOT.

Problem with most auto engines including rotaries is that power peaks are usually developed at 5000-7500 rpm. You can't develop rated power at 1000-3500 rpm below power peak plus a FP prop is partially stalled at low airspeeds leading to poor acceleration and thrust. With a Lyc, power and torque peaks occur at almost the same rpm and are very flat so a FP prop works pretty well on a light aircraft like an RV.

Yes, it does seem that Tracy is getting pretty decent fuel flows compared to the Powersport guys.