Hi Paul,
As far as I know, Rotamax rotary engines do not have any oil sump,
they work with oil direct injection. In your opinion, is that a
good thing or not? Would you recommend oil sump or oil direct
injection? I am looking to get 350 Hp out of a 2 Rotor engine, in
all aluminum.
please see following picture of a Rotamax engine.
http://www.indysportaviation.com/Oshkosh2008/rotamax120hp.html
Thank you Andy Mangold
It is called charge cooling and it is inadequate for an aircraft
engine called on the generate over 50% power for long periods of
time.
You will need a high pressure oil system with oil cooled rotors. In
other words a Mazda.
Paul Lamar
Paul, Thank you very much for the info. I am planing to run the two
engines only on 50%, even for take off. Only in case of emergency,
when one engine is failing, the remaining engine has to go up to
100, but only for about 5 minutes. In a case like that, would you
say it is OK?
Andy Mangold
Good luck. Might work.
The rubber coupling they used also failed causing a crash.
Paul Lamar
The charge cooled rotary engine and the 2 stroke piston ignition
engine seem to suffer the same defects : - low fuel efficiency, -
large amount of oil in exhaust gas, - not suitable for high charge
base load operation. - not suitable for turbocharging (and
turbocompounding, of course)
and also share some good points : - simpler and lighter than their
counterparts, - automatically lubricated in any position.
So they are suitable for the same applications that require low
power for limited time and high peak power to weight ratio as RC
models, chainsaws,...
Philippe Dejean (France)
Guys. thanks for all the info.
Does anyone know the weight difference between an all aluminum two
rotor engine and a engine with iron cast side housings?
Also does anyone know if I can mount the two rotor engine just on
the Bell Housing?
Andy Mangold
The bare cast iron Mazda weighs 190 pounds. The bare all aluminium
Mazda weighs about 110 pounds.
It is possible to mount it with the bell housing but probably would
require some tig welding on the bell housing. Send me a sketch of
what you have in mind.
Do you have a gear box?
Paul Lamar
Again thanks for the info.
About the mount, you can see two PDF drawings in the attachment.
I do not have a Gear Box. I could mount the engine right at the
front of the Block. The engine will be hooked up direct to the
drive shaft with a flex coupling between. Then the driveshaft goes
on to a center gear with a reduction for the propeller. The same
on the opposite side. The drawings are with the Rotamax engines
and those have mounting points on the belly and on the top.
That is the reason why I am asking, if I can mount them just on the
front/ to the Block on the Shaft side. That strange form around the
engine is made out of carbon fibers and serves as Engine mount and
also for the landing gear, which you can not see on these
drawings.
Andy
That will work but you only need two rubber bushings on that end of
the engine. One on the other end. That is all you need to locate an
object in space. The two rubbure bushing react the torque from the
engine.
Read this.
Hi Paul, As far as I know, Rotamax rotary engines do not have any
oil sump, they work with oil direct injection. In your opinion, is
that a good thing or not? Would you recommend oil sump or oil
direct injection? I am looking to get 350 Hp out of a 2 Rotor
engine, in all aluminum. please see following picture of a Rotamax
engine.
http://www.indysportaviation.com/Oshkosh2008/rotamax120hp.html
Thank you Andy Mangold It is called charge cooling and it is
inadequate for an aircraft engine called on the generate over 50%
power for long periods of time. You will need a high pressure oil
system with oil cooled rotors. In other words a Mazda. Paul Lamar
Paul, Thank you very much for the info. I am planing to run the
two engines only on 50%, even for take off. Only in case of
emergency, when one engine is failing, the remaining engine has to
go up to 100, but only for about 5 minutes. In a case like that,
would you say it is OK? Andy Mangold Good luck. Might work. The
rubber coupling they used also failed causing a crash. Paul Lamar
The charge cooled rotary engine and the 2 stroke piston ignition
engine seem to suffer the same defects : - low fuel efficiency, -
large amount of oil in exhaust gas, - not suitable for high charge
base load operation. - not suitable for turbocharging (and
turbocompounding, of course) and also share some good points : -
simpler and lighter than their counterparts, - automatically
lubricated in any position. So they are suitable for the same
applications that require low power for limited time and high peak
power to weight ratio as RC models, chainsaws,... Philippe Dejean
(France) Guys. thanks for all the info. Does anyone know the
weight difference between an all aluminum two rotor engine and a
engine with iron cast side housings? Also does anyone know if I
can mount the two rotor engine just on the Bell Housing? Andy
Mangold The bare cast iron Mazda weighs 190 pounds. The bare all
aluminium Mazda weighs about 110 pounds. It is possible to mount it
with the bell housing but probably would require some tig welding
on the bell housing. Send me a sketch of what you have in mind. Do
you have a gear box? Paul Lamar
Again thanks for the info.
About the mount, you can see two PDF drawings in the attachment.
I do not have a Gear Box. I could mount the engine right at the
front of the Block. The engine will be hooked up direct to the
drive shaft with a flex coupling between. Then the driveshaft goes
on to a center gear with a reduction for the propeller. The same
on the opposite side. The drawings are with the Rotamax engines
and those have mounting points on the belly and on the top.
That is the reason why I am asking, if I can mount them just on the
front/ to the Block on the Shaft side. That strange form around the
engine is made out of carbon fibers and serves as Engine mount and
also for the landing gear, which you can not see on these
drawings.
Andy Mangold
You only need 2 rubber bushings on one end of the engine. You need
at least one on the other end. Otherwise there will be a lot of
bending on the plate.
I am curious. Where did you find 2 rotamax engines?
Is it a one rotor or two rotor?
Paul, coming back again about all aluminum rotary. Is an all
aluminum two rotor engine with oil cooled rotors suitable/doable to
be turbo charged with up to 10lbs pressure and producing about
350Hp? And is a configuration like this still reliable?
Andy Mangold
Are you kidding? :-) Where have you been? :-)
Try 650 HP.
Haven’t you heard about our time to climb project?
Yhe turbo compound rotary is going to replace the small turbo prop
engine.
Paul Lamar
Wow, I like to hear that, it lets my heart pump faster!
In your experience, to gain 350Hp out of a two rotor engine, how
much turbo boost will be necessary? Or is it possible to reach
that even without a turbo? I am asking because Adam from
rotaryengine.com has concerns running a all Aluminium Engine with
more than 6psi boost. For 10psi boost he would put more studs in.
Andy Mangold
In P port form it will generate up to 300 HP at 9 or 10,000 RPM.
We are running about 25 to 30 inches of boost. The engine is robust
to say the least.
Usually people use 1/2 inch tension bolts. If you want to save
weight you can use titanium tension bolts. Check out Mazdtrix on
google.
Paul Lamar
Paul, to calculate the gear ratio for my counter rotating Rotor gear
I need to know, roughly with how much rpm does it generate 350Hp.
Andy Mangold
To get that much HP you are going to need a turbo changer.
The gear boxes are usually 3:1 so for a 2700 max RPM prop
max engine RPM will be 8100 RPM.
Paul Lamar
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