TopCat110

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Chris and All,

Hello! This is officially my first post. I have had a JHH Kfir hanging in my garage for over 20 years and after getting bored with my foamies, I'm doing a electric conversion using the turbax fan with the Scorpion HV 4035-800kv motor. I'm going to run 12s after being totally star-struck by Chris' Mirage III RS.

I'd like to get a email also with the plans for the nose and main doors if you could. Also, is the 7.5 cg good for this plane too? I lost the plans years ago some how...

Tonie

Jet20

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Hi Tonie,

Your best bet is to contact my folks via email ([email protected]) or phone (652-467-0260) and you can order a set of plans. There are quite a few sheets. Since your kit is of the same generation that my IIIRS was from, I would highly recommend purchasing the updated inlet ducting (especially since you want to go EDF) as well as the foam wing. Do you plan to build this as a Mirage or Kfir?


Chris

storrie23

Hi All
I have a Byron KfirBUT I need a pair of wings.
any help ?

Chuck

Mark 5

Hello Tonie, if you have the 42 inch foam wing Kfir, the CG is 7 1/2 inches measured from where the leading edge of the wing touches the fuselage.The Kfir is a great flying airplane,I wish they were more of them flying.

Jet20

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Yes, for the KFIR configuration. For reference, the Mirage (no canards) is I think about 1+" further back from that. Interestingly, on my IIIRS which is kind of a hybrid Mirage/KFIR the CG falls in between the two, though closer to the mirage than KFIR. I say hybrid as it has the Mirage III wing (no LE sawtooth) with a KFIR inspired canard that's about 75% the size of the canard on the KFIR and placed further back on the fuselage than the KFIR also.


Chris

ps. pics curtesy of Uncle Joe and SunDevilPilot

TopCat110

My Feedback: (1)

Thanks for all the feedback. However, you've all got me a little scared now... The wing is measured at 37" so I'm assuming this is the scale wing? Also, AUW is coming in at 14lbs! I'm really nervous now. Am I building a wood pile (as Larry said to me once in his store when I was getting a load of balsa to build a nitro A-10).

Jet20

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Topcat,

Nice looking Kfir! I don't think you have anything to worry about...my IIIRS is almost 17 lb and it flies great on our 12s E-Turbax setup. I think I built the thing out of bricks! Anyways, on the CG, I think that the 7.5" CG is close for the configuration you have, but will have to check the plans which I won't be able to do until after I get home from work tonight. I'd say call my folks (which you could still do), but they are at this point probably setting up for the AMA expo this weekend.


Chris

Jet20

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Hi Tonie,

It was nice meeting you at the AMA show. I checked the plans (finally!) and the forward CG location for the scale wing is shown at 7-3/8" back from the wing saddle, rearward CG was 7-3/4".


Chris

bandit_av

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Hi

We maiden our Kfir a month and half ago and the C.G was approx. 7.5 inch and it was noticeable that the nose was very heavy.
the landing was very hard landing and the left wing tip and the left gear were damaged, so now it is almost before painting.
in the next flight I will to take the C.G to something between 7.75 to 8 inch.
the plane was powered with the Wren SS and it was sweet in the air.
By the way, we put gyro on the alirons as I was afraid it will tackle me, but it took off straight ahead without any bad habit
beside a very nose heavy.

Enjoy the plane
Avi

Mark 5

Hi Avi, Sorry to hear about your hard landing. Please let us know how it flies when you move the CG back. I bet that the Kfir was over powered with the Wren SS. Tell us a little more about the maiden. Mark

bandit_av

My Feedback: (1)

Hi Mark Hi all
Mark, This is our way of life with this hobby don't you think? as my partner says, we took a very very old thing and made it like almost new,
but there is always something to remained us that this an old thing... .
I'm not sorry about the damage, because I'm stubborn guy and after I have decided with my self that I'm going to "win" it, I will win it! It is a challenge.
After that I don't really care as long as the instruments and the turbine will stay alive...

Chris, you have a beautiful Kfir/Mirage!!

Avi

babish

Hi Avi

The landing gears are almost ready, are you ready???

I believe that the next landing will be like sliding on butter as you usual do.

bandit_av

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Ofir my man !

You are great!!

Thank you a lot!!

Avi

Jet20

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Avi,

Thanks for the kind words. Sorry to hear of the mishap. I can relate. My mirage was extremely nose heavy on its first flight. It took me about 6-8 flights to really get the CG honed in where I wanted it and now it flies on rails! I actually moved it a bit too far back at one point and the airplane started to hunt in roll at that CG location which I found really interesting. Moving it back forward again solved that issue.


Chris

Mark 5

Chris, your Mirage is a real beauty! I saw the video, great flying airplane, sick amount of power.Have you flowen the Mirage/ Kfir on turbine and if so which do you prefer?

Jet20

My Feedback: (2)

Thanks Mark. I've not flown one of our Mirages with a turbine actually, so can't really compare. I would imagine it would fly equally as well if not better. I originally intended my mirage for turbine, but switched to EDF during the final stages of the build. Just didn't have the coin for the turbine and I really enjoy flying the big EDF stuff.


Chris

TopCat110

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Status Update:
First engine test with Scorpion 4035 - 800kv engine and Turbax set up. Went extremely well. Amazing amount of thrust. Will put on a scale or meter to get actual thrust (lbs) soon. Scheduling taxi test later in the week.

Question: Chris or Avi, did either of your planes need to be set up with a couple of degrees of up elevator? I have a SR-71 and it is designed to have 2 degrees of up elevator. Any thoughts on this? Or do you have it set up neutral.

Tonie

bandit_av

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Hi Tonie

Have all the best of luck!
Concerning to the elev. , the elev. setup is 0 deg. but the canards are has 1-2 down thrust deg. which means they are giving some constant up,
but! make sure to mix in your radio the ali. with the elev. especially for the up movement, as you will need all the up movement you could get
especially for the rotation. BTW, this setup is in the real full scale plane.
All the above is for split elev. and ali., not if you have done elevons ( I haven't noticed if you have elevons or split elev. ali.).

Avi

Jet20

My Feedback: (2)

Yes, you will need to carry some up trim. My airplane carries about 1/4" of up trim which is more than I expected. I'd recommend starting with maybe about 1/8" for the maiden.

Also, Avi brings up a good point on the elevator setup. If you have the split aileron and elevator surfaces, I highly recommend using them as elevons, or if nothing else mixing your elevator control with the ailerons. The airplane does need the whole trailing edge to act as elevator to have good pitch control/response.


@ Avi, Love the picture!


Chris

TopCat110

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@ Chris and Avi,

Thanks guys. Heading out to the garage shop right now and putting in the suggestions.

Tonie

Mark 5

Chris, you can borrow a turbine from your father! Better yet,dont ask, just take.

Jet20

My Feedback: (2)

I wish that were true!

Mark 5

I recently bought my Kfir back from the person I sold it to 3 years ago. Then I moved the CG back about a 1/2 inch and increased the elevator throw a little. I finally got to fly it again at the Oil Creek Oc-turbo fest in Titusville Pa. I had a tiger by the tail. After moving the CG forward and reducing the elevator throw, the Kfir flew great.