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3W Bearcat with Moki 300

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3W Bearcat with Moki 300

Old 04-08-2020, 10:40 PM
  #301  
Detlef Kunkel
 
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Originally Posted by mitchilito View Post
Hey Detlef, I would still love to hear more about your Moki 300 fuel induction mods. Can you tell us a little more about that?


Hi Mitch,

I sent you a PM about that topic with the Moki 300
Old 04-09-2020, 06:01 AM
  #302  
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Exciting. Now I have to make a spinner mount (itís just sitting there) and the ďafter-spinner fairingĒ which runs from the back of the spinner to the engine crankcase- just like the full scale Bear.


Old 04-26-2020, 10:31 AM
  #303  
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Turns out I had to make significant thrust adjustments to get it to a place I was finally satisfied with. Has just a tiny bit of down thrust.



Old 04-26-2020, 10:42 AM
  #304  
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Made the spinner backplate out of many layers of vacuum bagged carbon. As you can see I drilled a million lightening holes. Before I did it was HEAVY. Glued and riveted mount points
for 3mm button head cap screws (on order).

Spinner is mounted and ready to run - minus burnt-orange paint.





Old 04-26-2020, 10:30 PM
  #305  
Detlef Kunkel
 
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Mitch,

this one gets better and better. Fun to follow your build

Canīt wait to see paint on it.

You already decided a paint scheme?
Old 04-27-2020, 02:56 AM
  #306  
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Thanks, Detlef. It really is starting to get fun now. I ordered - and received - a mask package from Callie Graphics for this paint scheme:


Wish me luck!
Old 04-27-2020, 03:03 AM
  #307  
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OMG I wish you all the luck you can get for this extremely demanding paint scheme.

A chap in Switzerland did this (99% sprayed, no decals) and it was a true challenge.

But a beauty in the air and on the ground, second to none.


Keep on the good work

Detlef
Old 04-27-2020, 02:21 PM
  #308  
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I think I know the guy you reference. His build made my build look like a monkey did it. I prayed there would be videos, but NO! Darn.

Made a mandrel so I could balance the backplate and then the spinner. Itís as well balanced as one can do without a dynamic balancer.



Last edited by mitchilito; 04-27-2020 at 02:24 PM.
Old 04-28-2020, 06:43 AM
  #309  
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Not a lot of cooling air inlet area - but a lot more than the full scale Bear!


Old 04-28-2020, 03:46 PM
  #310  
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I was thinking of our friend Detlef as I took this opportunity to do a rough CG check. He expressed concern about my decision to put the two elevator servos and the rudder servo waaaaay back in the tail. However, my DC-7 cowl and giant spinner add SIGNIFICANT weight to the nose.

Anyway. As it sits in the pic below the CG is about 3 inches in front of the wing tube.

Hey - it finally looks like an airplane!!



Last edited by mitchilito; 04-29-2020 at 12:12 PM.
Old 04-29-2020, 11:42 PM
  #311  
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Hi Mitch,

the difference was that I was lacking the heavy spinner, AND I had a scale but not light-weight tail gear ( 420 gr complete with everything, including wheel etc).

I could NOT afford 2 servos in the tail.

Maybe our engine mount is comparable, then your pretty spinner way ahead of the CG counts a lot on the other side :-).

Then I would guess your cockpit area is a lot lighter than mine. The guy that had built my cockpit was pretty generous about weight, the entire take-out cockpit had 1050 gr. Not really slim.




Again- good work

Last edited by Detlef Kunkel; 04-29-2020 at 11:46 PM.
Old 04-30-2020, 03:21 AM
  #312  
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Thatís a good assessment, Detlef. But we wonít know until itís done, right?! I can always move the heavy rudder servo up front etc. and my cockpit is going to be light indeed. I ordered the pilot bust yesterday, 100 grams and the instrument panel assembly, maybe 50 grams. Itís going to be very simple and light. ďStand offĒ scale for sure.

I was worried the stock canopy would be unsuitable for this Rare Bear version but after careful trimming Iím happy with it. Hard to tell much difference in these pics but this is the finished canopy trim:


Hard to believe John Penny could see out of that thing!!

Last edited by mitchilito; 04-30-2020 at 03:24 AM.
Old 05-06-2020, 02:27 PM
  #313  
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Brazed up the 2-into-1 today. Got the pre-fluxed rod from Vogelsang. Expensive but really easy and effective stuff. A little goes a long way so maybe itís not so expensive - per use. . .

Itís a little scary brazing these pipes on. Once you braze them they are on for life. You have to destroy them to get them off! Better do it right the first time!!!




Last edited by mitchilito; 05-06-2020 at 02:34 PM.
Old 05-21-2020, 08:41 AM
  #314  
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The never ending battle continues: it was time to block the wing oil cooler inlets. The final version of Rare Bear completely eliminated these but the paint scheme I want has these reduced inlets. Yes, they slant down a little inboard side.





Old 06-01-2020, 06:03 AM
  #315  
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After drooling over Detlefís big 28 mm gear actuating cylinders I couldnít take it any more. We always knew my whimpy stock Century Jet cylinders would be marginal (22.4 mm) so I decided to see just how much bigger I could make my cylinders. Turns out MUCH bigger. My pistons are now 28.7mm! I will now have power to spare.

Stock cylinder on the right



This is what my blueprints look like. I know, pretty archaic ☺️

Last edited by mitchilito; 06-01-2020 at 02:27 PM.
Old 06-01-2020, 02:28 PM
  #316  
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What happiness looks like.



Old 06-03-2020, 02:49 PM
  #317  
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Here are the cylinders final assembled and pressure checked (good).



Old 06-07-2020, 06:46 AM
  #318  
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Default Breaking news!!!!

Now that I have finished every single thing thatís not painting I find that Iím unwilling to spend the next six months (or more) painting before I get to fly it. SO:

Iím going to put a quick ďtestĒ paint scheme on it. If and when I get it working well I will put on the final livery. This means I will be flying in a month or two - YAAAAYYYY!!

This will be the ďtest schemeĒ:



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Old 06-09-2020, 08:18 AM
  #319  
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That is not a bad scheme, if you can see the colors when it is flying.
Old 06-11-2020, 04:59 AM
  #320  
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Just for fun I ran the numbers on my new gear cylinders:

original: .875 piston, 34 pounds of force@120psi

new cylinder: 1.0 piston, 94 pounds of force@120!!

Almost triple the force of the original cylinders. Amazing how that works.



Last edited by mitchilito; 06-11-2020 at 05:08 AM.
Old 06-11-2020, 06:20 AM
  #321  
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Hi Mitch,

I bet you wont regret the big cylinders.

you would even appreciate them more if you had made your ( probably sad) experience with the smaller ones.

Very good work you show here :-)
Old 06-14-2020, 05:17 AM
  #322  
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Thanks, Detlef.

Hereís a picture of things that need to be painted. NOT INCLUDING THE WINGS!


Old 06-16-2020, 03:59 AM
  #323  
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Taking care of last minute details before paint: I finally got around to balancing the ailerons. This aircraft is FAMOUS for aileron flutter.

You can see the plugs to fill the holes I used to insert 2 ounces of epoxy/lead shot in each leading edge.

With my overbuilt landing gear and weighted ailerons the wings will be pretty heavy.



Last edited by mitchilito; 06-16-2020 at 04:33 AM.
Old 06-18-2020, 01:30 PM
  #324  
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Well, folks, Iím a little surprised I find myself nearing the end of this nearly impossible project. Primed everything but the wings today.



Wonít be long now
Old 07-06-2020, 03:03 AM
  #325  
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Nice Work Mitch.

I was not lazy either ( although pretty slow)

There are more than 2.5 years of project time and a few kÄ on the table.




The middle one is mine, on the left Marios, on the right Chris (who wants to paint his I think silver).




The U/C is probably the most complex one I have built so far.

Let's leave out my old Cessna 337 RG and A-7 Corsair II (too long ago);

The 1/4 P-40 was already very complex, the Jeanie ( P-47 1/4,4) with its oil damping and air suspension, which was switched off for retraction (with shortening of the telescope) was also not trivial, including very close resemblance to the original (at that time also measured in Duxford). That was more work.




But the Bearcat U/Cs is even more complex in terms of its components and overall geometry, plus the task of making sure that the locking mechanism is bullet proof to withstand the loads.

We calculated thrust forces in the rigid strut beyond 175 kilos. The holding forces in the lock reach a quarter of a ton (!)




There is a reason why the latch is so elaborate and was made of chrome steel.




I (you can see it on the pictures) wanted to have a predetermined breaking point with this enormous leg length. You can see the separation in the upper leg head. Its presence has challenged the construction of the telescope enormously, concerning the remaining length for the large spring travel including 2 step spring and oil damping.




You can't see it from the outside, but inside there is not a single mm unused or just loitering around senselessly.

The space is so completely used that the leg needs an external breathing chamber towards the end of the travel (air connection with hose on top of the leg). The telescope itself has a remaining volume of ZERO at the top.
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