The Grumman X-20 has to be one of the Sexiest Planes every designed. Super KEWL Swept forward wings with forward canards.
I've admired this plane since first seeing it years ago. Last year actually in November I noticed Dragon had produced a 1:144th scale "Warbirds series" plastic model kit. I just had to have one.
A week or so later the package arrived at the house and I opened it with great hope of converting it for MMX flight.
UGH! alas this little 1:144th model was Way to small to accept the minimum diameter T2+(.281") motor tube. and the over all model was only about 4-3/8" long including the aerospike (4-1/8" without).
Dejected I re-boxed the kit and put it aside to work on a bunch of other Micro PMC's I had in the Que.
About a week ago I again was lured to the X-29's sexy design boxtop.. and again Opened it up to really take a hard look at what it would take to make it fly.
Still WAY to small for the required T2+ Body/motor tube I decided some major body surgery was going to be needed both outside and inside this little model to have any chance of converting it. Removing the Aft fuselage at the second panel line while filing out in styrene with a round file to paper thin wall thickness just barely passed the body tube. This left a long distance from the Body Panel line just behind the cockpit to the aft end of the main Landing gear bay for a T2 shoulder. Adding about 3/8" to the needed extension length our shoulder was epoxied into the now seperated Nose section inside the Air intakes forming a natural locking system.
Complicating getting our T2+ in the aft end of the model was the fact the bottom fuselage panel included the Main Landing gear bay recess which had to be all but ground through to pass the tube. Extending the T2+ out the back to where the model exhaust nozzle would have been only gave a total T2+ length of 1-7/16".
Since the Main gear bay had been more or less saved I decided to make this model a wheels down configuration.
Due to extremely limited space I had to cut the Shock-line down to 28" of 70lb kevlar with a 1/4" x 6" orange PTFE Streamer/Wadding. Yep I got it all in there LOL!!!
Our Cardboard Cut-out showed the model would need about 4.1g of Nose weight. 4.1g! even using #9 lead shot that was a lot of tiny balls. I Hollowed out the cockpit putting in a false bottom, after gluing up the forward wheel well and gear it was all be ground off from the inside. The interior styrene walls were thinned as much as I dared. filled every tiny space with Shot. I even added a lay of shot to the exposed surface of the cockpit, covered it with epoxy and sanded smooth adding one last shot as the pilots head. Looks like it should be stable with a MMX-II motor.
Dragon did a outstanding job of detailing the landing gear, alas I was afraid the tiny spars would not take flight landings so a rear reinforcing plate of .005 waferglass (G10) was epoxied to the main gear and carefully filed to profile.
That's about as far as i've gotten on this little project.
Since I really didn't think I was going to pull this one off, I didn't take many progress photos while working through the problem areas...My Bad, Sorry. but I'll try to be a little better as the finishing and decaling go along.
With all the nose weight this little 4-1/8" model already tips the scale a 10.3g, Should be an interesting little flying Micro PMC.
Heres the Pics I have so far
I've admired this plane since first seeing it years ago. Last year actually in November I noticed Dragon had produced a 1:144th scale "Warbirds series" plastic model kit. I just had to have one.
A week or so later the package arrived at the house and I opened it with great hope of converting it for MMX flight.
UGH! alas this little 1:144th model was Way to small to accept the minimum diameter T2+(.281") motor tube. and the over all model was only about 4-3/8" long including the aerospike (4-1/8" without).
Dejected I re-boxed the kit and put it aside to work on a bunch of other Micro PMC's I had in the Que.
About a week ago I again was lured to the X-29's sexy design boxtop.. and again Opened it up to really take a hard look at what it would take to make it fly.
Still WAY to small for the required T2+ Body/motor tube I decided some major body surgery was going to be needed both outside and inside this little model to have any chance of converting it. Removing the Aft fuselage at the second panel line while filing out in styrene with a round file to paper thin wall thickness just barely passed the body tube. This left a long distance from the Body Panel line just behind the cockpit to the aft end of the main Landing gear bay for a T2 shoulder. Adding about 3/8" to the needed extension length our shoulder was epoxied into the now seperated Nose section inside the Air intakes forming a natural locking system.
Complicating getting our T2+ in the aft end of the model was the fact the bottom fuselage panel included the Main Landing gear bay recess which had to be all but ground through to pass the tube. Extending the T2+ out the back to where the model exhaust nozzle would have been only gave a total T2+ length of 1-7/16".
Since the Main gear bay had been more or less saved I decided to make this model a wheels down configuration.
Due to extremely limited space I had to cut the Shock-line down to 28" of 70lb kevlar with a 1/4" x 6" orange PTFE Streamer/Wadding. Yep I got it all in there LOL!!!
Our Cardboard Cut-out showed the model would need about 4.1g of Nose weight. 4.1g! even using #9 lead shot that was a lot of tiny balls. I Hollowed out the cockpit putting in a false bottom, after gluing up the forward wheel well and gear it was all be ground off from the inside. The interior styrene walls were thinned as much as I dared. filled every tiny space with Shot. I even added a lay of shot to the exposed surface of the cockpit, covered it with epoxy and sanded smooth adding one last shot as the pilots head. Looks like it should be stable with a MMX-II motor.
Dragon did a outstanding job of detailing the landing gear, alas I was afraid the tiny spars would not take flight landings so a rear reinforcing plate of .005 waferglass (G10) was epoxied to the main gear and carefully filed to profile.
That's about as far as i've gotten on this little project.
Since I really didn't think I was going to pull this one off, I didn't take many progress photos while working through the problem areas...My Bad, Sorry. but I'll try to be a little better as the finishing and decaling go along.
With all the nose weight this little 4-1/8" model already tips the scale a 10.3g, Should be an interesting little flying Micro PMC.
Heres the Pics I have so far