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BMW 1200 R

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Inambu33

New Member
Joined
Jul 6, 2020
Messages
3
Hello!
I would like your input on using a BMW 1200 R on a Polliwagen kit.
If it is a good idea, do you know any knowledgeable and experienced person or shop to do the job?
Thank you.
 

Will Aldridge

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Oct 30, 2009
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Location
Northern Utah
Well depending on which psru you go with you're instalation will weigh as much as 80 lbs less than the o-235 that it was designed for. Which means you're most likely going to have to extend the motor mount considerably to balance the plane.

Here is a KR2 with its traditional Volkswagen engine:
kr-thinksmall.jpg2.jpg

Here is another KR2 with a BMW R1200:
20190430_155055.jpgimg_1174-2.jpg

Note the difference between the distance from the firewall to the back of the engine and I think the weight difference between the 2 is 30 to 40 lbs.

Now you could certainly add ballast but if you wanted the lightest instalation possible we'd be naming your plane Pinocchio(really long nose). The long nose would destabilize the aircraft and make the rudder and elevator less effective. That's just one example of some of the issues that you face. Not saying it's not doable but there are some challenges.
 

Inambu33

New Member
Joined
Jul 6, 2020
Messages
3
Thanks a lot for your help, in fact I didn't buy the Polliwagen kit, I'm just researching ahead to see the viability.
Another small two seater that I like is the Quickie Q2, whow do you think the BMW 1200 R would fit it?
 

Will Aldridge

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Joined
Oct 30, 2009
Messages
957
Location
Northern Utah
Thanks a lot for your help, in fact I didn't buy the Polliwagen kit, I'm just researching ahead to see the viability.
Another small two seater that I like is the Quickie Q2, whow do you think the BMW 1200 R would fit it?
The answer is pretty much the same as above. The Q2 was designed around the Volkswagen engine. You'll get more hp for less weight. But again you have the balance issues.

Edit:
Seems like you've picked your engine and are now trying to pick an airframe. Usually better to pick your mission, then pick the plane for the mission and budget.
 
Last edited:

Doran Jaffas

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Joined
Jun 25, 2019
Messages
240
I agree with the advice given. If you enjoy building with the prospect of rebuilding more than flying and know to or know people to lessen the risk factors and have more money to spend then then have at it and the best to you.
Otherwise, sticking with the proven engineering is usually the safest, time saving and cost efficient way of building.
Both types are needed. BUT the first mentioned are less likely to complete their birds.
 

Lendo

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Joined
Feb 6, 2013
Messages
522
Location
Brisbane
The KR2S is a better option IMHO. The BMW Motor is OK but needs a good PSRU. Just research everything.
George
 

R90s

New Member
Joined
May 3, 2020
Messages
1
Hello!
I would like your input on using a BMW 1200 R on a Polliwagen kit.
If it is a good idea, do you know any knowledgeable and experienced person or shop to do the job?
Thank you.
BMW has a rich aeronautical history. They currently have no aeronautical products. BMW folklore holds that this is a strongly held principle and they actively object to use of their products in airplanes. Considering the insane liability climate associated with aviation, one can not criticize them - even though they manage the liability situation of one of the highest power motorcycles on the market. The point is that the desire for a shop or dedicated person to lead one through the use of this engine in an airplane is not feasible.

I personally come from a motorcyclist background and find research on this subject enjoyable. The first page of a google search on “BMW engine aircraft conversion” turns up a significant fraction of the internet sites I have found in two years of casual reading.
As already mentioned, airtrikes.net is your first stop. The second is the build described in Willkommen of a Cherry Bx2. Interestingly, the Cherry leans heavily on the KR-2 for ideas. As mentioned In Spang-air writeup, the source of the happiest BMW oilhead conversion process is:
The takeoff website is mostly in German, but google translate will make it easy to browse.
In the end, in spite of my new tech Motörhead inclination, I personally decided on a Wynn Williams Corvair conversion.
 

Inambu33

New Member
Joined
Jul 6, 2020
Messages
3
BMW has a rich aeronautical history. They currently have no aeronautical products. BMW folklore holds that this is a strongly held principle and they actively object to use of their products in airplanes. Considering the insane liability climate associated with aviation, one can not criticize them - even though they manage the liability situation of one of the highest power motorcycles on the market. The point is that the desire for a shop or dedicated person to lead one through the use of this engine in an airplane is not feasible.

I personally come from a motorcyclist background and find research on this subject enjoyable. The first page of a google search on “BMW engine aircraft conversion” turns up a significant fraction of the internet sites I have found in two years of casual reading.
As already mentioned, airtrikes.net is your first stop. The second is the build described in Willkommen of a Cherry Bx2. Interestingly, the Cherry leans heavily on the KR-2 for ideas. As mentioned In Spang-air writeup, the source of the happiest BMW oilhead conversion process is:
The takeoff website is mostly in German, but google translate will make it easy to browse.
In the end, in spite of my new tech Motörhead inclination, I personally decided on a Wynn Williams Corvair conversion.
Thank you for your input.
 
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