TR2

[Bradley Walker]

When I started out to make a totally new design AND make the design expressly for mass production, I had no idea how really tough it would be.  Not to mention heartbreaking.  One thing to remember in engineering projects, prototypes are for testing, not for showing off.  Anyway, TRX 1 has been finished, flown, and retired.  Now I am working on TR2.

The only real issues with the project so far are not based on the aerodynamic package, but instead have been construction and weight related.  The Devil's in the details!!  The first proto was simply far too heavy and the engine was too low.  Any weight under 70 oz should fly great, over that...cough cough ahem.  TR1 was about.... a lot more than that.  Right now TR2 looks to be heading for about 62-64 oz with a paint finish with about 1.5 oz of tip weight.  With the film finish, I think 56-60 would be closer to the norm without a pipe or big 4 stroke.

One interesting wrinkle.  I wanted to try aluminum mounts.  On a hunch I bought the OS Max aluminum mounts for the OS 52 FS from Tower.  I knew I had switch PA's and RO Jetts with the OS Max 52 using the same mounting holes.  Well, the OS mounts come pre-drilled and fit my PA 65 (with slightly oversized mounting holes) perfectly!!!  Even the distance to the nose is perfect.  The OS mounts are like all OS metal parts, very nice (like a jewel).  For me, this is drop in.

[Larry Cunningham]

Pretty awesome.

Looks HEAVY! No, I don't mean in weight, I mean it's HEAVY, Daddy-0.
Lots of good engineering evident. What did you do differently with the
bellcrank mount (you said the first one failed)? This one looks very substantial.

Quite a model, Brad. Obviously a lot of effort went into its design, particularly
for mass production.

L.

"Most of my cliches aren't original." -Chuck Knox, NFL football coach

[Phil Coopy]

Really cool Bradley.......will it look like my '57 TR3?

Phil

[Bradley Walker]

What did you do differently with the
bellcrank mount (you said the first one failed)? This one looks very substantial.

Well... it is kind of interesting.

Originally all of Brodak's ARF/ARC planes had one piece wings.  I actually submitted the bellcrank mount that is shown here for the Strega for the first run of one piece wing run of models (i was a kit reviewer).  It is the standard bellcrank I have used for years and years and comes from foam wing type construction.  From what I understand they used this mount.

Now due to more restrictive packaging criteria, it was determined that future models would need to have two piece wings.  The factory created a bellcrank mount similar to what is used on the smaller planes for the T-Rex.  The bellcrank was hung from two plates but the plates were not attached to the fuselage sides.  While this mount is fine for smaller planes, I tested this new mount.  It failed. 

The TRX will have a mount similar to the one shown.  The bellecrank is hung from a long music wire, then the plates are installed on the top and bottom of the wing after it is joined.  The wire is trapped in placed by outside wheel collars (and JB Weld is my recommendation).  Then the plates are glued to the inside of the fuselage upon installation of the wing into the fuselage.

This mount is so critical that it simply overshadows everything else in the whole plane.  If not done correctly, it will fail.  So, it must be done right!!!

[Chris McMillin]

7th grade favorite.

[Bradley Walker]

2nd grade favorite:

[john e. holliday]

Brad, seeing the pictures makes me rethink ordering a T-Rex.  May have to get venturis for the 70 four stroke I have.  Hope all works out.  Have fun, DOC Holliday

[Bradley Walker]

Check this out.

I have been wanting to find a bullet proof substrate that could go straight onto the SLC film without the paper.  For TR2 I simply do not have the time to add the silkspan, so I decided to do some mad scientist stuff.

One thing I know is that these auto clear coats stick to anything.  I mean they stick like iron.  So I wanted a auto clear base to grab the film because I LOVE the way auto clear sands.  When it is fresh it just powders off with open coat dry paper (this comes from doing numerous repairs).

I used Omni clear.

I wanted some color so I added some base coat hugger orange (the same as the color that will be used for the plane) in about a 4 to 1 ratio.

I used fast clear activator and added accelerator to make it even faster.

I added three oz of baby talc.

Reduced it 150%.

Then I just started dusting this on.  Dust Dust Dust  then a little wetter until I shot all 16 oz of material (2.5 oz of weight added).  The finish turned out matte due to the talc.  After an HOUR (an hour) I did some test sanding with 400 dry.

OMAGAWD!!!  This might be awesome.  It sands WHITE, and the low spots are still orange so you can see all the flaws like sanding silver.  It just powders off leaving a GLASS SMOOTH SURFACE!!!

[Larry Cunningham]

That seems to be working well.

Here's a little trick I found for looking a bit closer at these photos.

Hold down the CTRL key and rotate your mouse wheel.. You can quickly zoom in on the photos for a better look.. I'll bet at least some of you didn't know that shortcut. If you did, why haven't you told ME about it all these years? ;->

L.

"Drawing on my fine command of the English language, I said nothing." -Robert Benchley

[peter jurczyk]

That trick works very well. I never knew that Thank You