Producer/Bushmaster Weight and Balance

[PA18project]

I am looking seriously at purchasing a tri pacer with the intent of converting it into a producer. My concern is weight and balance. It seems to me that lengthening the fuselage almost 24" creates an amazing lever arm. Even with an O-360 up front it seems that weight and balance might be difficult to get correct.
The plan is to make the plane as light as possible with the major modifications consisting of: lengthening the fuselage; rebuilding the wings to make them the appropriate length; supercub style gear up front; and supercub tail feathers. Any insight would be appreciated. Thanks.

Brad

 

[don d]

are you thinking certified or experimental????

 

[PA18project]

Im thinking experimental on this one although my understanding is that it can and has been done as a certified aircraft. Unfortunately I really like to wrench on things and Im excited about the prospect of building a light Producer type airplane over the next several years.
The plane, as it sits is a box of parts for all practical purposes. The wings are complete, the fuselage is in good shape and the rest of it falls comes to me in cardboard boxes. The whole project is amazingly complete but nonetheless a box of parts. The project comes with paperwork but the plan is to either deregister it or otherwise sell the paperwork (if that is even legal) to someone who can use it to revive a certified tripacer. Since the project is already disassembled except for the wings the remaining disassembly basically includes removal of the controls and instruments from the fuselage and disassembly of the wings in preparation for rebuilding them. Hope this helps. Thanks.

Brad

 

[N7623H]

Hi Brad,
I'm doing the same thing, soon as I get all the projects done my wife wants me to. I'm in two minds about what to do about the engine and have spent some time with an A&P down the road who did one.
He used an O320 and extended the mount to offset the weight caused by lengthening the fuselage. I have a 160 hp O320 on the plane now but am considering using an O540 instead. We eyeballed the numbers and the 540 on a standard Maule engine mount should work on the wt & balance. Anything smaller will need to be hung on a lengthened mount.
Good luck.

 

[don d]

Brad;

I did an experimental like you are considering (10 years ago). Useed a 200hp IO-360 and constant speed. Built my own motor mount. Some things I would do alittle different now. My plane was still in the hanger yesterday. 1194 empty. Alot of info on this site about the subject.

Don

 

[PA18project]

Thanks for the replies. I am trying to avoid hanging a 540 on the front but had considered that route. I should probably run some numbers on fuel burn. It might be comparable at low power settings to what I would see with a 360 or even 320 at 75%?
Glad to hear that some have lengthened the engine mount. The thought of cutting into the area between the instrument panel and firewall to make up the length had me scared enough not to attempt the project.
What do/did you guys think of the planes once finished?
Again, the plan is to make mine as light as possible. Set up with enough instruments for night VFR and no rear seats. Thanks again for all the helpful input.

Brad

 

[JimC]

If you want to keep it light, what about using an ECI IO-340 or O-340. It's lighter than an O-320 and has about 175 hp. With high compression pistons, you could probably get about 180 hp out of it.
JimC

 

[plnecrazyone]

bushmaster w&b

Hi guys,am working on a bushmaster with a 34" strech and an O 470,am trying to post a photo? hum,cheers,nick[/url]

 

[TJ400]

I too am building a Producer/Bushmaster experimental from a PA-22... Fuselage is lengthened, gear is made, tail feathers nearly complete and now working on SuperCub wings....

Following the wings, the motor mount will need fabrication... From what I recall from an experienced builder's plans and calculations, I think the mount is extended 10 inches further than stock to correct weight and balance... We are using 320's 150HP.... fuselage was lengthened 24 inches...

A very labourous project but very rewarding too...

tj

 

[Flapman]

A Maule motor mount will bolt right on the PA-20 fuselage and place the motor further forward for weight and balance help. I don't recall which model Maule off hand. Sounds like a great project, keep us posted.
Regards,
Flapman

 

[Grant]

Can anyone point me to a photo of a "Producer" I am curious about what they are.

 

[5381Z]

This is the Dakota Cub Super Pacer. Essentially the same thing.

http://www.dakotacub.com/new_page_27.htm

Mark

 

[TJ400]

I like to think of it as a "four place SuperCub" with a usefull load of 1000 lbs... A little more or little less.... A very impressive performer....

 

[Airwrench]

Build a Producer, I think that it is a great way to go. I've had mine 26 years. If you search the Old Super Cub photo gallery for "Producer" you will find some pics. - Steve

 

[jeanch]

What will be a good empty CG location for the Producer ?

I am making verifications for a friend at the moment...

 

[Steve's Aircraft (Brian)]

Here is the thread that I started about a local stretched pacer http://www.supercub.org/phpbb2/viewtopic.php?t=11721

Modifications on these airplanes can be extensive, or mild. Only limit is your imagination and resources. Keep in mind the aircraft will be an "EXPERIMENTAL", so you can set your weights and CG's to your liking. The Daringer (see thread above) uses the original PA-22 CG locations and he set his gross weight at 2600 lbs. Empy weight on this one is 1321.

Brian

 

[jeanch]

I remember your thread Brian. Impressive modifications !
So if you keep the original CG range of the pa22, then how would you determine that engine mount length ?
Do you want to go back to the empty PA22 balance ? Do you just make sure the most rearward CG configuration is in the range ?
Or the most frontward loading brings the CG as close as possible to the frontward limit ?
These can lead to different solutions, no ?

 

[Steve's Aircraft (Brian)]

He based his extension on keeping the CG of the engine the same as the CG of the engine on a Super Cub. His total airframe extension's put the aircraft the same length as a Super Cup. Based on the test flights, it seems to have worked out correctly.

At least that what Darin has told me, most of his modifications were done simply on the "I wonder how well this will work?" method. Nothing that was done was "tried and true". If fact, during the first flight, he was explaining out load that all that work and money invested would be for nothing if the airplane didn't performed very well.

A lot of people can beat around the bush all day long to theorize what mod is best and how to do it, Darin is the first guy I know that just did it to see if it would work. And quite frankly, that is what home-building is all about - trying something new and putting it to the test.

Brian.

 

[PA18project]

engine mount lengths?

For those of you who have done a stretch pacer, producer or bushmaster
I know there are a number of variables but I am curious if you would be willing to post-
What length is your engine mount from firewall forward compared to the length you extended the fuselage and -
What engine did you install
Any other variables you care to share would be appreciated like empty weight, weight on the tail or other special considerations.
Seems the general consensus is that the original piper mount is too short.
Some have recommended to use a maule mount but I have not been able to find anything out about which one.
Thanks

Brad