JohnHab

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That looks amazing. Wonderful job.

mitchilito

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Well, I can't believe it. After almost SEVEN YEARS I'm finally in final assembly! Today I installed the rudder and the canopy latch. Both came out fantastically. I did all this prep work so long ago I honestly can't remember! I can say this: it's going to progress VERY quickly now because I have long since done ALL the hard stuff.

EDIT: Can I beat Detlef to maiden flight????

Detlef Kunkel

Hi Mitch,
I am happy with you about your great progress.

In Summertime, I myself am not very often in my workshop, and therefore there only slow progress on final assembly here.

Do you already know where exactly you will put the CG?

mitchilito

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Detlef, I thought we talked about CG somewhere on this thread, no? I was going to ask you where to put it because I know you've already flown one of these airframes.

mitchilito

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Hinged the stab and installed servos. They’re just trial fitted here.

Detlef Kunkel

Thats where it would be due to my simple calculation.

But for some reason, the BC should be flown with a more forward CG

I gave all my old documetation away when I sold the BC I years ago, really too bad.


I think 3W recommends 190 mm and I flew mine between 200 and 210. went perfect.


Of course a little depending on Pilots taste

mitchilito

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Thanks for the info, Detlef. This number (I'll shoot for 205) is from the leading edge of the wing where it meets the fuselage, correct?

I have a Xicoy balance machine which I can't wait to put into use once again.

ForcesR

Using this CG calculator program will tell you where the CG should be located. It's simple to use and it has never failed me especially when doing a maiden flight. https://rcplanes.online/cg_calc.htm

Detlef Kunkel

Mitch,

I forgot that you have clipped wings.

I would start with 200, I can truly confirm that this works very well.
You can alway go a little aft if you fine trim the Cat later.



Funny, I also purchased the Yicoy scales last week. A friend has one and we weighed my Trojan and T-33 the other week.

I liked it so much that I ordered a Set ( 100 kg Version as I also habe some heavies as well)

mitchilito

My Feedback: (7)

200 it is then. Shouldn't take long now although I have to work through making sure my landing gear is going to work to my satisfaction. I'm pretty optimistic.

Detlef Kunkel

Funny how parallel our final turns out.


First wing is fully functional

mitchilito

My Feedback: (7)

Amazing, Detlef. Also interesting how DIFFERENT our two projects are. I'm NOT the scale master that you are, Detlef, but I think my Rare Bear is turning out great. I took the time to weigh everything today to get an idea about CG and total weight. CG is looking amazingly close. It actually seems that it will be just a smidge NOSE HEAVY. Can you believe it?!
Total weight - minus radio, air equipment and gas tank: 48.53 pounds. I would guess final weight will be very close to 53 pounds.

EDIT: Minus cradle total is 47 lbs even YAAYYY!

Here is almost everything fuselage related. Tail is complete with servos and tail wheel installed . I picked it up on the wing tube (with the cowl in the proper place) and it balanced dead on 200mm!! I could NOT believe it and. . . . .




. . . . here is what all that weighs


I stacked everything else I could find onto the sales (the landing gear are under there) and. . . .

. . . .here's what that weighs.

Whoops, forgot the wing tube. . . .

. . .It's not light

Also forgot the gear doors. . . .

. . .which weighs this much. Bottom line: she weighs a grand total of 48.53. I'm pretty happy with that figure. Especially since the balance is fantastic.

EDIT: I forgot to subtract the cradle which weighs 1.53 lbs. Actual total 🟰 47.0 lbs. Yaayyyyy!!

gow589

My Feedback: (1)

Just for reference


, my Ziroli with clipped wings (from 84" to 72") with a 100cc weighed 34lbs:

Detlef Kunkel

Hey Mitch,


absolutely no question that your Bearcat is a wonderful piece of art, second to none (!!)


I am not surprised by your weighing result. VERY close to mine, what else..


With the 300, everything is totally easy concerning CG. Put everything where you like it best and it fits perfect.




My wing is ready.

8 kilogram Grumman Goodies including Servos & tube

I am sure your clipped wing is lighter

mitchilito

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That was a cool plane. You mentioned your spinner came apart (several times?)

I'm REALLY hoping mine doesn't do that! I built it pretty damned stout. Solid carbon thru and thru.

We'll see. . . .

mitchilito

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Here's my servo setup for the the elevators although ALL my servo mounts are identical to this: Carbon fiber plates with machined mounts and these indestructible servo arms I found somewhere. They really are the BOMB.

gow589

My Feedback: (1)

Thanks! Both of them were spun aluminum:

gow589

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The first Bear I made was a practice airplane for the one I spent more time on. I lost the first spinner on it. It departed the airplane on a high speed pass. I was able to coax a little power out of it with half a propeller to get it back to the field. Upon landing, the wing was held on by one bolt and I pulled the firewall off with a little tug.

mitchilito

My Feedback: (7)

That poor pilot got blasted up there!

mitchilito

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Some teaser shots

Detlef Kunkel

[QUOTE=mitchilito;12777113]Some teaser shots



Absolutely stunning :-)

Detlef Kunkel

[QUOTE=Detlef Kunkel;12777115]

Absolutely stunning - and so different :-)

At the moment, my progress is pretty nice.

Wing - done

tail - done

RC installation - 65,34 %

Tank & pump - done

4 cowling flaps - done



This weekend, the engine installation is planned.

I borrowed 2 pushrods to a friend, he lost them due to sticking valves. Old story. You MUST take care of that and lubricate them very frequently, causing the enging room to look VERY scale after 2 flights :-)

New ones came today from Airworld. So the 300 is shortly complete again.

I really want to see how she looks on her long legs, and that is really close ahead

Detlef Kunkel

I think I posted this before? not sure


When I took off the heads for the second time ( reaming the guides for more play) I machined lubrication tubes into the exhaust guides.
A machine job, no free-hand

Only exhaust is needing this, inlet lubricates itself from the oil gasoline mixture.
Every 2 flights I give it a (central = red arrow) push with teflon lubricant. It works and saves uncounted disassemblies of prop and cowling. 3 lost pushrods and 2 bent ones were enough to make this solution reasonable.

mitchilito

My Feedback: (7)

Detlef, I can't thank you enough for this post. This is something that I need to get started on. I think I'll pull one of the heads today and measure out the exhaust valve guides to get an idea what kind of reamer to order. You've said it before but it's crazy we have to go through this with a $5K engine. But WOW is it worth it in the end.

One question: what kind of red flexible tubing is that that will take the heat of that cylinder head, especially on the exhaust side? I would think only silicon would take that kind of heat.

Detlef Kunkel

Thats only a simple pneumatic gear tube ( 3 mm outer dia) that I use for my retracts.

Well air cooled, never failed.

Silicone likes to fail sometimes if used for certain mineralic oils . As always- tests will make you cleverer :-)

--------------

BTW
funny what "experts" are discussing seeing this red line system.

Even "he goes turbocharging the engine " was one of the estimations :-)


Simply great fun :-)