• Welcome aboard HomebuiltAirplanes.com, your destination for connecting with a thriving community of more than 10,000 active members, all passionate about home-built aviation. Dive into our comprehensive repository of knowledge, exchange technical insights, arrange get-togethers, and trade aircrafts/parts with like-minded enthusiasts. Unearth a wide-ranging collection of general and kit plane aviation subjects, enriched with engaging imagery, in-depth technical manuals, and rare archives.

    For a nominal fee of $99.99/year or $12.99/month, you can immerse yourself in this dynamic community and unparalleled treasure-trove of aviation knowledge.

    Embark on your journey now!

    Click Here to Become a Premium Member and Experience Homebuilt Airplanes to the Fullest!

Push/Pull twin Sport Plane

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

rhbelter

Active Member
Supporting Member
Joined
Mar 9, 2015
Messages
36
Location
Carmel CA
10/8/21

Ahoy, Airplane Homebuilders,

Below, I offer my concept of a ‘Push-Pull’ twin airplane. Seldom seen, for various reasons.

My thinking on this subject is that the rear engine presents both CG and aerodynamic base drag challenges, and that a suitable drag-fix extension shaft is a further mechanical challenge.

I submit that my solution solves these problems, and results in a seriously fast low cost sport plane.

My credentials are just fine, but more than 60 years out of date, while retired in Carmel CA. Accordingly, I offer concepts, with little significant engineering, but with some detailed design. If enough of you like the concepts, the engineering will follow, to make this airplane happen.

The airplane: Side by side, push-pull, twin boom, retractable gear. Rear prop shaft. All easy -- yuhh!!!

Fuselage: Steel truss work. Aerodynamic shape by some suitable method. A composite shell, easily removeable, would be nice to live with.

Surfaces: Pretty much alum 6061, pull riveted. Some members may want carbon fiber. Eventually?

Landing gear: Steel weldment, with air bags. Will be ‘bouncy’, like a spring gear. Add shocks? Much lighter than a spring gear. A bit more work, but good fairing of a fixed gear is not easy, and still not as good as ‘not there’. Low-cost. I have done a fair amount of detailed design of the landing gear. The landing gear which I offer is NOT high tech. It is a ‘Blacksmith’s wet dream’.

Actuators: I suggest CO2 or nitrogen, regulated to whatever the highest pressure that components can handle. PLC control.

Engines: AeroMomentum AM15 @147hp. Near 300 hp in a little clean airplane like this will be fast as a sport plane!! I chose the AM15 because it is a fine value. The airframe is sized to accept the forthcoming AM2.0, and with 520hp available, will be awesome, and ‘hotted-up’, will likely do well in the Reno Racer’s Sport Class.

My plans were that there be a drive shaft of aluminum, or carbon fiber, coupled with Guibo’s. The best way to do it is to de-mount the PSRU, relocate it, and couple it with a shaft, but I have not yet asked Mark Kettering for his opinion. The short shaft will look a lot like the one in your car, with a critical speed well above the max rpm of the engine.

The aft engine with the extension shaft, plus a spinner, will nicely solve the base drag problem.

Bail out: Not with that spinning prop back there. A rear prop brake is indicated, and a forward prop brake may be appropriate. Controllable pitch/feathering props would be nice, but likely not seriously needed in what is intended to be a quite high performance but fairly low cost sport plane.

How to make this happen???

Form a committee ?????? There is a famed expression that says. ‘A camel is a horse designed by a committee’.

There clearly is enough competence among the membership to do the engineering, detailed design, and component fabrication. IF there is enough interest, there will also be members to devise an organization to bring this airplane to life. NOT me, at 93 years!! Interested members can offer their skills in the various disciplines. If this is successful, there may by some money to be made. ‘Not rich, but less poor’.

IF IF there is interest, my suggestion is to build one prototype. Then, with success, IF there is continued interest, that a limited number of ‘beta’ versions be built, with the possibility of forming a company to produce kits.

I suggest the following disciplines be included, with a manager of each.

Fuselage

Engines, forward, and aft

Rear shaft/hub

Surfaces and flight controls

Landing gear

Actuators and PLC electronic controls



My son is ‘untouched’ by any technical education, but is able to set-up, and manage a web site. He has further skills in marketing. He is willing to do this early ‘heavy-lifting. As the project takes shape, Zoom meetings will keep everyone informed, plus an agreed on engineering system -- probably EAA Solidworks. Try for an annual meeting at Oshkosh. Please note my use of ACAD. I have never become proficient at the preferable system.



My credentials include a career as a TailHook Naval Aviator, MS aero, Navy Design Officer of the A6-E Intruder (400+ built), Skipper, NavPro Bethpage, buying all of their Grumman Navy airplanes, including the first 70 F-14 TomCat Fighters, (I REALLY know how to spend money)!!



My final Navy job was as the F-14 Deputy Program Manager. The Deputy job was a lot of fun, since my Boss spent every day building briefings and doing budget drills, leaving me available to run the program.



Enjoy /s/ Bob Belter [email protected]
 

Attachments

  • Document (5).pdf
    309.9 KB · Views: 151
Back
Top