I have a project and the plans for the Graham Super Midget. I also have the plans for the Bushby MM, and the Nexus Mustang. I've studied the Polen Special extensively. They all share some basic heritage from Bushby.Seeking plans for the Graham Super Midget Mustang. Any and all information appreciated.
Thanks in advance.
Thanks for the reply and insights, Monty. Can I text you? (925) 998-9240.I have a project and the plans for the Graham Super Midget. I also have the plans for the Bushby MM, and the Nexus Mustang. I've studied the Polen Special extensively. They all share some basic heritage from Bushby.
Keep in mind while reading this the Busby and Graham MM were designed to use a C85. There are some mods made to the current design allowing larger engines. Up to a 0360....Though I would be very careful with the airspeed.
The Polen is probably its own thing. Polen may have based it more on Graham than Bushby, with the fuselage loft changed to work with the cowl off a twin (Piper I think). The Polen wing looks to be the same as Graham, with a continuous spar all the way to the center of the fuselage. the instrument panel bulkhead is attached to the spar, and the entire fuselage/wing is an assembly which cannot be taken apart. This makes transport an issue if the aircraft can't fly. The Graham project I have uses Swift mains for the landing gear and has a fixed tail wheel. Polen has a retract tail wheel, and I believe the same mains. The MM has a center section truss that bolts to each wing so the wings can be removed. These attachments are the structural limitation on the MM. Nothing wrong with them as designed, but mount a bigger engine and you could have issues. I would be leery of a 200 hp MM....The airplane will do 200 mph with an O-200...what more do you want?? I don't know what structural beefing up the Polen has in the wing spar area if any. My numbers show the Graham spar to be plenty strong for larger engines within reason.
The Polen and Graham fuselages are stretched and beefed up VS the MM. More bulkheads and stringers. The fuselage is not an issue for any reasonable engine choice. The real weakpoint of the Graham desing is the tail. The Graham tail structure is similar to the MM. It is more "elegant" in design, but harder to build. I'll note that the Polen suffered tail flutter and had to upgrade to a carbon tail. I've never seen the structure of the Polen tail, but I wouldn't be surprised if it's similar. The tail is the main structural issue that limits top speed and larger engines should be looked at with a jaundiced eye unless the tail structure is addressed.
The Nexus is the best IMHO. The wings are removable. The center section is from the M2. The fuselage is stretched and beefed up just like Graham and Polen. The loft is fixed. The tail is reinforced and fixed. MUCH stronger tail. More like the RV in design. Designed for larger engines and two people.
You would be far ahead starting with the Nexus and figuring out how to adapt Swift or some other retracts to the design. Get rid of the passenger and you could afford a 6 cyl and its fuel. Much better starting point than either Graham or Bushby.
As always DYOR. None of this is engineering advice, and only my opinion. Assume I'm an insane idiot, and you may not be far off the mark....etc, etc.
I am going to scan the Graham plans eventually. The plans are quite extensive and large format. I just haven't gotten around to it yet. I'm currently beset by many other more pressing projects.
For those interested, there is information about the flutter modes of the Polen. High level summary (slide show) hereThe tail is the main structural issue that limits top speed and larger engines should be looked at with a jaundiced eye unless the tail structure is addressed.
I read through that presentation. Not really enough info to make a good judgement. Until I see ground vibration and flight test data that confirm frequencies, color me a skeptic. Especially since the future work is to obtain a better structural model.......big red flag there. This is more of a first pass look at the problem.For those interested, there is information about the flutter modes of the Polen. High level summary (slide show) here
Flutter Analysis of the Polen Special II Emphasizing Addition of a Wet Wing and Ailerons to Flutter Model ASE463Q [Fall2002] Final Presentation Structural. - ppt video online downloadPresentation Outline Polen Special II Background and Specs Project Motivation and Objectives Past Polen Group Work Flutter Theory AMAFALA Objectives Completed (Results) Conclusionsslideplayer.com