Dear Mr. Lamar

Thank you for your rotaryeng.net  web page. You
put such an incredible insight into the world of Wankel rotary engines,
it's almost unbelievable that such website exist online.

Since we share same belief in Wankel rotary engine as a light aircraft
engine of the future, I wanted to show you my concept aircraft.

Two years ago I started conceptual design of a six seat light twin
engine aircraft that is designed around G-300 Mistral engines.

After many months spent on design and calculations I ended up with
aircraft that has cabin size of a light jet, turboprop aircraft
performance at a price point of a twin engine piston aircraft.

For example, cruise performance would be around 270 ktas at 25000 ft
with 35 gph of avgas or mogas on typical 500 nm trip (including climb,
cruise and descent fuel).

As you know, major benefit of Wankel engines would be reduced operating
cost resulting from: longer engine TBO, cheaper overhaul prices and
ability to use mogas.

I believe in Wankel rotary engines and I noticed that the biggest
problem with them is that there is no airframe that is optimized for them.
So I designed this one that can be used for air taxi, medical services,
cargo, etc.
In this missions, it would stand out from turboprop and piston aircraft
with its low operating cost and increased cabin comfort, this way it
would really show the true advantages of Wankel engines.

Here is the link for a web page where you can see how it looks like,
http://dragannristic.wixsite.com/art660


I would like to hear your opinion about this aircraft.

Looking forward to hearing from you.


Best regards,

Dragan Ristic

Looks great. I think you will need a gear box and a larger prop diameter.
The rotaries  make power at 6000 RPM and  up. We are running the 650HP
200 pound turbo
2 rotor Mazda engine at 8000 RPM We have a 3:1 gear box but a 4:1 single
planetary gear box
would work better if we could find one at reasonably cost. The prop is
84 inches in diameter.

It surprised even me when it did not blow with a 100 inches of Hg
manifold pressure.

Paul Lamar


A twin Wankel-powered, 6-seat plane would be amazing. Something you
wouldn't be afraid to cross oceans with. Here's another link to an
interesting twin pusher under development;
http://www.hensleyaircraft.com/
 No
mention of engines planned, but one can imagine.Don't know how real it
is; tried contacting them and so far no response. The only other twin
experimental project I've heard of is the Gemini from Zenith, but it
seems to have been abandoned. You'd think there would be a market when
you consider the expense and bother of certified twins.

Oh yeah, is there a PSRU/Gearbox available to counter rotate one of the
engines?


Bob Ripley

Lower fuel burn than PT6's and one third the cost.

It would have to be experimental but probably one third of the airplanes
sold are experimental kits now a days.

Certification for the engine  would be very expensive even if a
certified fuel injection
and mags were used. It should be an exact copy of the Mazda to minimize
technical risk. The big cost is casting the steel lined rotor housing. I
think
the thing to do is sand cast a steel liner in an aluminum rotor housing.

I know that can be done as I have seen that done in an aluminum foundry
here is So Cal. Not rotor housings but other parts.

I don't think so on the off the shelf auto tx gear box parts.
That would have to be custom made.

Paul Lamar


Nice looking concept.
I wonder about your claims for gravel though........
I work on similarly sized aircraft (piper navajos and beech kingairs)
operating off of gravel, and you would be amazed at the amount of rock
damage to the flaps and horizontals from gravel thrown up by the landing
gear.
I would hate to see how much damage your props would take if operated
off of gravel.

Beautiful work though, I like the look.

Narfi Willem


Mr. Paul

Very impressive numbers, 650 HP 200 lbs engine, give me two of those for my airplane and we could chase those light Citations and Phenoms.

It would have to be experimental until we prove to the world that this Engine/Airframe combination is far superior than other GA twins.

When we prove that is superior and reliable, I think that certification won't be a problem because we will have enough demand on the airplane to justify investments in certification.

Until then, owners of experimental would have benefits of flying on mogas and using Garmin G3X avionics with all of its options.


Yes I think there would be a market for this type of aircraft, just look to the companies like Wheels Up, Surf Air and Cape Air.

Cape Air even partnered with Tecnam to develop aircraft for their needs called P2012.
Wankel twin would be perfect for air-taxi because it would reduce operating cost for at least 100 USD per hour only on maintenance expenses.

Unfortunately, currently there is no PSRU available on Mistral G-300 engine that can counter-rotate one of the engines.

Mistral developed PSRU on their own already and I think that they can build one that counter-rotates if there is demand for such product.

The only solution I have for this problem is to use some sort of protection on wheels.

Something like covers on nose wheels of IL-38 aircraft could be used to overcome this problem.


Dragan Ristic

Here is a full power run video. Notice the stretch in the half inch nylon rope holding is back.
The water vapor coming out of the blow off valve on the top of the engine means
it is running at 71 inches of Hg. We can set that up to 100 inches with out blowing it up.
80 inches gives us 650 HP.  There is no oil cooler needed with 3 gallons of Mobil One.
The water temperature never gets above 140 F.

For those of you with cell phones and tablets. You must save the file first.
Tablet and cell phone email programs do not tell you what folder it is in so you then
need ES File explorer to list all the movies and try to find it.

If you find it, ES Explorer will give you choice of movie players. So you need to install
half a dozen different ones to find one that will work with mpeg format. Some that work
well for my 4.4.2 version of Android are MX and Video Player. Other versions of
Android may require other movie player versions.

The sound is misleading. It sounds nothing like what you are likely to hear.
It is like standing next to a jet engine at full power. It is 130 db which means
it will permanently  damage your ears unless you are wearing a head set.

Paul Lamar


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