News:


  • March 29, 2024, 05:16:15 AM

Login with username, password and session length

Author Topic: Possible T-50 Build  (Read 2298 times)

Offline Ed Prohaska

  • Trade Count: (0)
  • Lieutenant
  • ***
  • Posts: 54
Possible T-50 Build
« on: August 27, 2015, 11:26:08 PM »
Family health issues have required me to give up stunt flying, so I've turned my attention to scale. I've only built one pseudo-serious C/L scale model, a red box Top Flite P-51 back in the late 1970s. I flew it at the 1982 NATS in Sport Scale; don't recall where it placed, but probably in the middle of the pack. I lived in Illinois in the late 1980s and 1990s and flew it in Chicago area contests and at Milwaukee. It did pretty well, mostly due to its "fly-ability" rather than fidelity to scale.

An OS FSR .61 flew it with authority (despite its 8.5 pound weight) and in wind conditions that would ground many other scale models. Flaps were coupled to the elevator as on a stunt ship and used to drop Vortac plastic "bombs". The photo is from 1983. I am the younger one with hair. The guy with his finger on the prop is my uncle, the late Col. R.H. Gaver (USAF). He flew gliders in WW II and later C-124s and was also a modeler.

Lately I've been toying with a project that may never be completed, but has been an interesting and fun diversion so far. Producing anything flyable could take years, but its fun to tinker. Its the Cessna T-50 Bobcat from Tom Morse plans. I bought these on eBay in "Nobler size" (50" wing span). The seller also lists them in what was probably the original 66" span and some larger sizes.

Plan A is to use two FP .25s and hope that's enough power. Just playing around with hardware, the 3-line bell crank, 2 engines, tanks, nacelles and my perceived need for a very strong (i.e. heavy) wing center section, I project a final weight that could easily top 5 pounds. I don't expect it to stunt, although an occasional loop would be nice, but do want it to be easily flyable and fun to fly, not under powered and not a "rock on a string".

Actual construction has not started yet, except for the stab and elevator. I don't like the result and will probably do another set. They look too small and a little too thick. I'll probably "fudge" and make a set about 15 to 20% larger; maybe with a slightly thinner airfoil.

The goal is to produce a "Bush League Scale" model that looks halfway decent and is very flyable, even if I never get to fly it. If flown in a contest it would be the Fun or Sport classes, not Authentic Scale. I am no longer set up to paint anything, so the finish will be mostly Monokote, possibly with painted nacelles. Some cockpit detail may get painted. I'd have to brush it or use spray cans.

A few questions: If I pick a color scheme and the closest Monokote color is off a shade or two, do I get zero points for color and markings or just docked a couple of points for the shade difference? One color scheme I like is shown in the attached photo. There are no numbers or insignia. So, do I get zero for markings because there are none, or full points because I was true to the scale documentation and did not add any undocumented graffiti? Are AMA numbers required on a scale model?

I did build a "mock up" of the inboard wing panel to play with installation of the bell crank, throttle control, nacelle construction, engine mounting, tank box and cowl. The actual model, if ever built, will have many changes, based on what I learned from this mock-up. It weights 1.5 pounds and is not even a whole wing panel !! No wood parts from this mock-up will go into an actual model. I built it for "tinkering" only.

I see others are building C/L versions of the T-50. It would be encouraging to see one get finished and hopefully fly well.

Offline Fred Cronenwett

  • 2016 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 2093
    • Lafayette Esquadrille
Re: Possible T-50 Build
« Reply #1 on: August 28, 2015, 04:58:11 AM »
I flew an A-20 with two OS-25FP's (great engines by the way) and it had lots of power. The model had a 41" span and weighed 5 lbs and it flew at 1/2 power, at full power the model would fly fast and I never used full throttle

I would not change the stab/elevator size, move the CG forward to stabilize the model. For CL scale purposes they are big enough, remember you are not trying to fly the stunt pattern.

on CL scale models the AMA number goes inside the model, the outside of the model should match the color scheme and markings of the full size exactly. There is probably an N-number somewhere on the full size. look on www.airliners.net to see if you can find more pictures of that particular T-50.

Fred
Fred Cronenwett
AMA CLSCALE7 - CL Scale
Model Aviation CL Scale columnist

Offline Bill Little

  • 2017
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 12676
  • Second in COMMAND
Re: Possible T-50 Build
« Reply #2 on: August 28, 2015, 06:04:07 AM »
Hi Ed,

Sorry to hear you can no longer fly stunt, but it's great to hear you are still going to be involved in C/L.  I say go for it!  Make it as scale as you feel comfortable with (you have flown scale at the NATS so you are not a newbie) and at least make it to the rules of one of the classes.  Then plug away and get it finished.  You will have fun with the build and the satisfaction of the finished model!  Great subject and plenty of documentation should be available.

Good Luck!
Bill
Big Bear <><

Aberdeen, NC

James Hylton Motorsports/NASCAR/ARCA

AMA 95351 (got one of my old numbers back! ;D )

Trying to get by

Offline Avaiojet

  • 22 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 7468
  • Just here for the fun of it also.
Re: Possible T-50 Build
« Reply #3 on: August 28, 2015, 07:07:22 AM »
Ed,

Congratulations! H^^

The T-50 is a great aircraft to model.

I'm glad you're taking the project on because I have extreme interest in the Bamboo Bomber, so I'll be watching.

I must say, I believe I do not know about Tom Morse T-50 plans? But I will look at my T-50 stash.

The T-50 is on my bucket list and I also have two R/C .25's to do the job. However, the .25's I have are not carved in stone.

Biggest issue with me is determining the size model to build? My plan is to check available fiberglass nacelles and scale the model around them.

Jim Fruit is the modeler who is building a really nice T-50. Here's a link to his Build.

http://stunthanger.com/smf/index.php/topic,32927.0.html

Jim's work is outstanding!

Good luck!

Charles


Trump Derangement Syndrome. TDS. 
Avaiojet Derangement Syndrome. ADS.
Amazing how ignorance can get in the way of the learning process.
If you're Trolled, you know you're doing something right.  Alpha Mike Foxtrot. "No one has ever made a difference by being like everyone else."  Marcus Cordeiro, The "Mark of Excellence," you will not be forgotten. "No amount of evidence will ever persuade an idiot."- Mark Twain. I look at the Forum as a place to contribute and make friends, some view it as a Realm where they could be King.   Proverb 11.9  "With his mouth the Godless destroys his neighbor..."  "Perhaps the greatest challenge in modeling is to build a competitive control line stunter that looks like a real airplane." David McCellan, 1980.

Offline Jim Fruit

  • Trade Count: (0)
  • Commander
  • ****
  • Posts: 316
Re: Possible T-50 Build
« Reply #4 on: August 28, 2015, 07:49:05 AM »
Ed:

I remember you from back in the 80's. I flew against you in some of those contests with a variety of airplanes.

I just can't believe your post. It sounds like you and I are following the same pursuits. I am scratch building a Bobcat right now. The current plan is to be ready for next years season and the Nats. Mine is a 60" span. It will be all electric with retracts and flaps. It is so ugly it is good looking.

I don.t know about your anticipated 5 pounds. I am about that right now without motors and a finish. Mine is bigger than yours, however. I recommend a painted finish. Monocote does not score well in the Nats, if that is intended to be your pursuit. There are many events in the rule books now that could apply to the monokote finish. I recommend that you pull up a scale rule book from AMA to help you decide how to pursue it. I also recommend that you go to the internet to find a variety of colors and many views. There are a bunch, including three views.

You and I are pursuing a very unique and rarely built model in control line. Good luck.

Jim Fruit

Offline Fred Cronenwett

  • 2016 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 2093
    • Lafayette Esquadrille
Re: Possible T-50 Build
« Reply #5 on: August 28, 2015, 10:46:14 AM »
I put together is webpage on our club website that talks about CL scale and some of the details

https://lafayetteesquadrillecl.wordpress.com/lafayette-esquadrille-cl/cl-models/scale/

Fred
Fred Cronenwett
AMA CLSCALE7 - CL Scale
Model Aviation CL Scale columnist

Offline MarcusCordeiro

  • 2013 Supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 1872
  • "Never fly faster than your shoulder angel"
Re: Possible T-50 Build
« Reply #6 on: August 28, 2015, 04:28:20 PM »
I like it!

Marcus
Live to fly, fly to live
Aces High!

"There's no try. Do or Do not." - Master Yoda

"Wealth and fame, he's ignorant
Action is his reward, look out
Here comes Marcus, man..."

Offline Ed Prohaska

  • Trade Count: (0)
  • Lieutenant
  • ***
  • Posts: 54
Re: Possible T-50 Build
« Reply #7 on: August 28, 2015, 11:20:41 PM »
What a surprise! I had no idea this post would generate such interest. Thanks for all the advice and encouragement! Since "Bush League Scale" is not yet an official event, this Bobcat will be for Fun Scale. When I start cutting ribs I'll make two sets, so if this one pans out I'll be able to quickly start another, and make it closer to scale, add more detail and possibly finish it with paint instead of Monokote. But that is all wishful thinking now. I've barely got started on this one.

Here are some photos of the stab and elevator that I may do over. They are not quite done yet. Since it will be take-apart, I can still use them, alternating with larger parts to see if there is any difference. These parts are relatively easy to make compared to the rest of the model. Soon after getting into the bobcat, it became clear that the structure between the nacelles and center of the wing will attract the lion's share of weight, strength, thought, work and time. That's why I made the mock-up of a partial wing panel.

I did fudge on the elevator counter weights making them oversize relative to the plans. The counter weights bolt on and anchor the hinge wire for the removable elevators and horn. I also added a little area to the elevators, but the whole thing still looks "too small". I'm not sure the model would even fly with these small parts. That said, if they are indeed scale, the "real" bobcat did fly with a proportionally sized tail and so should the model.

One problem was that I started cutting parts and squirting CA before doing hardly any research on the full scale Bobcat. I have since gotten much information off the web and bought Paul Matt 3-views on eBay. They show lots of exterior detail. A rough calculation suggests that, to be scale, my stab/elevator span should be about 1.5 inch larger then the one I built. I'll recheck my figures before making more parts. These drawings are very well done. They could probably be enlarged to any desired size and used as a basis for model construction, especially in conjunction with the Bob Morse plans (not Tom Morse as I incorrectly wrote in the first post).

I did cut a set of template ribs for making more rib sets to build an actual wing. While doing the mock-up I noticed that some ribs are incorrectly shaped and not the right size for their position in the wing. The forward spar notches line up OK (sort of) but the rear ones are way off. I opened them all up anyway to use larger wood sizes for the spars. I won't cut out the flaps, but might cut out and hinge the ailerons and use them for trim tabs if needed.

I cut the ribs with a jig piece left on the bottom. The 1/16 inch slots in the front and rear are for the bottom leading and trailing edge sheeting. I trued up a pretty accurate shape for the tops of all the ribs and the bottoms where the sheeting slots are located. The "idea" is to pin and/or glue the jig pieces to the building board, check alignment in every axis, glue in all spars and then slide the bottom leading and trailing edge sheeting in the slots and glue it while the ribs are still anchored to the building board.

Lastly I'd glue on part of the top trailing edge sheeting before popping the structure off the board. The rib bottoms, fore an aft, between the spars are then "free formed" to their correct shape and the bottom center sheeting added. Center and LE sheeting for the top would be added after control system, nacelle, main gear and power pod components have been full engineered. Notice I did not say permanently installed or glued in place, as the intent is to make all these components removable.

I'm using the template ribs now to mold a few pieces of leading edge sheeting and hope to cut a set of actual ribs over the weekend.


Advertise Here
Tags:
 


Advertise Here