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KMP F-7F Tigercat

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Old 04-06-2008, 05:35 AM
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Default RE: KMP F-7F Tigercat

Hi guys I have been reading with great interest all of the post and coments and I still come back to one very important point.

Ok the original aircraft flew alledgedly on RCV 91's....correct. I am under the impression that fuji or Zenos are significantly heavier than the former said engines and unless there as far forward as possible, ie in the nose then they are dead weight and only make the model heavier. I have also noted that many guys have gone to great lengths to add scale doors, diffrent retracts etc in an attempt to make the model more scale and in departing from the original model and this in turn would make the model heavier and add higher flight loads to the airframe. So buy my understanding if the original ideas were followed to the letter and the model is kept "simple" then it may well be possible to build a much lighter model and come close to the original specs.

cheers Rossco
Old 04-06-2008, 06:09 AM
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Default RE: KMP F-7F Tigercat

Hi Rossco i did not add doors or other scale detail and used os 91f/s the weight was still 28.5 pounds dry 91f/s are NOT enough to fly while it does get in the air it needs a little more to keep it going120 f/s would be ok i think

regards

Anthony
Old 04-06-2008, 11:19 AM
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Default RE: KMP F-7F Tigercat

The one assumption being made is that the original prototype and the kit being sold are the same. Kinverflyer has said several times that THEY ARE NOT. Different size and different construction materials.
Another idea forwarded is that you can remove 4 pounds from in front of the CG in order to make a 26.5 pound airplane 22.5 pounds; and still have a flyable airplane. Even though the weight is not in the nose it is still ahead of the cg. You can't just remove it with no consequences. I'm not going to try that on any airplane I own. Others may proceed as they see fit. The guys sharing their assembly tips and warnings here only seem to have the success of all of us who own the kit in mind.


ORIGINAL: bignuts181

Hi guys I have been reading with great interest all of the post and coments and I still come back to one very important point.

Ok the original aircraft flew alledgedly on RCV 91's....correct. I am under the impression that fuji or Zenos are significantly heavier than the former said engines and unless there as far forward as possible, ie in the nose then they are dead weight and only make the model heavier. I have also noted that many guys have gone to great lengths to add scale doors, diffrent retracts etc in an attempt to make the model more scale and in departing from the original model and this in turn would make the model heavier and add higher flight loads to the airframe. So buy my understanding if the original ideas were followed to the letter and the model is kept "simple" then it may well be possible to build a much lighter model and come close to the original specs.

cheers Rossco
Old 04-06-2008, 03:59 PM
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Default RE: KMP F-7F Tigercat

Here's a brain storm or backfire...I am thinking of using another smaller 3/4 inch alum tube and run it thru the center section holes that are for the wires and epoxy it in. I was also thinking I could do a similar action in closer to the leading edge and use an alum 1/4 inch bar stock (rod or sq). I guess I could use the bar stock instead of the tube....

I think this could beef up the center section enough to support my version with the Saito 170's.

Comments?

Update , Just read VK's update and I have found a section iof 1/8 inch by 3/4 inch har stock that will do nicely to add just a bit of reinforcement in the center section. I will use this rather than drilling thru the ribs to add in a smaller bar + it'll be a lit easier.

I am continuing with my build and will have the wing completed this week. I am still figuering out the placement of the components in the fuse...

Old 04-06-2008, 05:39 PM
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Default RE: KMP F-7F Tigercat

T-CAT BROS, I TALKED TO PAUL KONDOR FROM KMP AT THE TOLEDO SHOW FRI., AND DISCUSSED THE CENTER SCETION ISSUE IN GREAT DETAIL WITH HIM. KMP'S POSTITON ON THIS ISSUE IS THE ONLY CENTER SECTION FAILURES ARE FROM TWO CRASHES, MINE(OAK TREE STRIKE), AND THE OTHER WAS THE CART WHEEL (TIP STALL ON TAKEOFF) CRASH. THE CENTER MOST PART OF THE CENTER SECTION ON MY PLANE DID NOT FAIL, ONLY WHERE THE TREE BRANCH WENT THRU. PAUL SAID THE ENGINEERING AND ASSEMBLY METHODS MAKE THE CENTER SECTION PLENTY STRONG AND THERE IS NO NEED TO BUTCHER UP THE WING TO INSTALL REINFORCEMENTS. THEY BUILD UAV'S FOR THE GOV'T USING THE SAME MATERIALS AND ENGINEERING METHODS AS THE T-CAT AND HAVE HAD NO WING FAILURES. AGAIN, THIS WHOLE ISSUE SEEMS TO BE DEBATIBLE. STILL NOT SURE WHAT MY DECISION WILL BE WITH MY BIRD....
Old 04-06-2008, 09:34 PM
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Default RE: KMP F-7F Tigercat

Check your PM
Old 04-07-2008, 12:31 AM
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Default RE: KMP F-7F Tigercat

Hi T-Cat builders. Center Section Discussion: I would rather be wrong about the strengthening of the center section then endanger myself and spectators. I will BOW to the importer. I still wonder why all major aircraft manufacturers still use a main spar construction? If our T-Cats had a honeycomb center section, I could understand the VOID of a connecting center spar. The material on my center section was thin balsa wood with fiberglass cloth and VERY BRITTLE. I will sleep well with a strengthened center section. PS. I'm still waiting to see pictures and names of the people who have PRODUCTION T-Cat (Like the ones we all have) that weigh 22 lbs. ready to fly. This is a GREAT hobby. Keep in touch...

Col. Chuck Winter
Old 04-07-2008, 04:52 PM
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Default RE: KMP F-7F Tigercat

T Cat Builders --- Center Section is COMPLETE.. Primer brushed on. Primer wet sanded. Primer airbrushed on. Wet sanded primer (Very Lightly). Airbrushed paint... Yes I will sleep better with a full spar in my wing..

Col. Chuck Winter
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Old 04-08-2008, 01:30 AM
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Default RE: KMP F-7F Tigercat

Hi Chuck,

your job looks good and I agree 100% with you - we will sleep better with the reinforcement of the centre-wing-section.

I also finished my reinforcement during last weekend.

Maybe A.Kondors comment is right that we do not need to do the mod. but in case you will pull too hard one day I am sure we could extend the life of our TIGERCATS with this mod.

My TC weights 30 lbs with 2x g26, SIERRA retracts and all geardoors operated and I have placed the fuel-tank in the centre-section - So I sleep much better with the modification ;-)

Maidenflight is scheduled for 19./20.04.2008 if wheathercondiitons will be ok those days....


best regards

Detlef
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Old 04-08-2008, 11:17 AM
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Default RE: KMP F-7F Tigercat

Hi Detlef, Thanks for the information and pictures. I am installing Fuji 24 engines in my T-Cat now. My T-Cat with these new engines will weigh 30 lbs. plus. What props have you decided to use? Best LUCK with your T-Cat.

Col. Chuck Winter
Old 04-08-2008, 01:38 PM
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Default RE: KMP F-7F Tigercat


ORIGINAL: VKerster

CHARLES AND T-CAT BROS, AFTER LOOKING AS CHARLES' PICS, I LOOKED AT MY WING FROM THE CRASH IN UDDER DISBELIEF. NOT ONLY DID MY CENTER SECTION LOOK LIKE CHARLES' PICS, BUT I FOUND THE LEADING EDGE HAS NO SPAR, AND THE TRAILING EDGE HAS ONLY A 1/8" BALSA SPAR!! I'M NOW CONVENCED I WAS RIDING ON BORROWED TIME UNTIL I WOULD HAVE HAD AN IN FLIGHT WING FAILURE. WILL POST PICS SOON.
FOR T-CAT #2, I'M GOING TO TRY TO INSERT A SMALLER DIA. TUBE FROM TUBE TO TUBE LIKE CHARLES, EXECPT I'M GOING TO TRY TO DRILL THRU THE RIBS THAT THE TUBES BUTT UP TO AND INSERT IT ONE INTO THE OTHER SINCE THE WING SECTIONS ARE NOT GLUED TOGETHER YET, AND USE J.B. WELD TO GLUE THEM TOGETHER. ALL OTHER IDEAS ARE APPERICATED. I WONDER IF THE FLY RC MAGAZINE ADDRESSES THIS ISSUE IN THEIR ARTICLE. I WISH KMP WOULD CHIME IN AND ENLIGHTEN ALL OF US HOW THEY WOULD FIX THIS MESS[:'(]............. TOLEDO IS NEXT WEEKEND.
VK where are you in this process?

If I understand your post correctly, you seem to be atempting what I have recently thought about, that is to place the smaller tube inside the existing wing tubes, breaking/cutting thru the rib where the tubes butt-up, and then JB Welding the inserted tube in place. Is this correct?


I am to the point where I have finishe all that can be done except for joining the wing together. I'd like to perform the centersectionextomy soon and want to see which rouye may end up the less complex.

Thanks
Old 04-08-2008, 01:46 PM
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Default RE: KMP F-7F Tigercat


ORIGINAL: VKerster

DETLEF, YOU ARE WELCOME. ANTHONY'S WING LOOKS LIKE MY FIRST T-CAT, THIN BALSA SKIN WITH GLASS CLOTH ON THE INSIDE AND OUT. MY SECOND CAT IS SKINNED WITH A KEVLAR COMPOSITE (LOOKS LIKE PAINTED CARDBOARD) AND SEEMS MUCH STRONGER. T-CAT#1 WAS FROM THE 1ST BATCH AND T-CAT #2 WAS FROM THE SECOND BATCH. I'M CONCERNED WHY ANDREW KONDOR OF KMP IS SO QUIET ON THIS FORUM CONCERNING ANTHONY'S WING FAILURE.................[&:]

VK What is the number on your no.2 plane? I have 79, not sure what batch that is in.

Thanks
Old 04-08-2008, 02:55 PM
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Default RE: KMP F-7F Tigercat

Hi Chuck,

thanks for your greetings.

I am using 16x8 3-blade MENZ props the G26 are turing those props with 7.100 rpm

An alternate for me would be a slim 16x10 3-blade carbon-prop from ENGEL supersilence.

Those 16x10 will be delivered during this week and Andreas Engel, the manufacturer told me, that I propably could gain a few revs and my TC could be a bit faster with those 16x10.

I will test them and let you know...



Old 04-08-2008, 05:18 PM
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Default RE: KMP F-7F Tigercat

Hi Detlef,
Could you send me a picture of your front noseleg door inside. I would like to see how you have done this. I have fitted Century jet retracts in mine. Should test fly mine also in the next 2 weeks.
Cheers Richard.
Old 04-08-2008, 06:03 PM
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Default RE: KMP F-7F Tigercat


ORIGINAL: CHARLES WINTER

Hi Detlef, Thanks for the information and pictures. I am installing Fuji 24 engines in my T-Cat now. My T-Cat with these new engines will weigh 30 lbs. plus. What props have you decided to use? Best LUCK with your T-Cat.

Col. Chuck Winter

Charles, I am proceeding with sliding a tube in thru the wing tubes and will JBweld in place once it is in place. My question to you is will that be sufficient or does the wood cross brace need to really be in there too?
Thanks
Old 04-09-2008, 01:39 AM
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Default RE: KMP F-7F Tigercat

Hi Chasman, I'll start out by saying that I think my center modification is extremely strong and very easy to accomplish. The added plywood spar is an additional strengthening member with the slow cure epoxy mixed with chopped carbon. To be direct with your question -- YES, put a plywood spar against the aluminum tube. The WEIGHT/STRENGTH ratio is very high (Low weigh high strength). Modelers have taken me up on my FREE offer of High Strength Aluminum Tube plus chopped carbon. Once you have the center section opened you might as well do a good job.

Col. Chuck Winter
Old 04-09-2008, 02:17 AM
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Default RE: KMP F-7F Tigercat

Hi Richard,

I will take pictures during next week and post them here. In the moment I am out for a business trip.

Cheers, Detlef
Old 04-09-2008, 05:30 AM
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ORIGINAL: Pylon2

Hi Detlef,
Could you send me a picture of your front noseleg door inside. I would like to see how you have done this. I have fitted Century jet retracts in mine. Should teat fly mine also in the next 2 weeks.
Cheers Richard.

Can you post it here?
Old 04-09-2008, 07:53 PM
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Default RE: KMP F-7F Tigercat

Here are afew shots of the nacelle with the Sierra gear and the fuel tank, and the center section with the small cutout and the 1/4 x 3/4 x 24 inch T-6 bar as the bridge for added support. The bar was slid in and has thick balsa caps glued in to keep it from moving the center sction will get some JBweld to hold it firmly.

The fuse nose section holds two 5400 Fromco Li Ion batts below the platform that holds a 3800 NiCad for the onboard glow and the onboard glow system.

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Old 04-10-2008, 04:00 AM
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Default RE: KMP F-7F Tigercat

Hi Chasman,

if I did no mistake I saw your 1/4 x 3/4 profile "laying horizontal" in the centre-tube but you would need it "standing vertically" so that the 3/4 plane is vertical and the 1/4 plane is horizontal to provide maximum reinforcement.


best regards

Detlef

Old 04-10-2008, 01:20 PM
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Default RE: KMP F-7F Tigercat

Yes, I thought of that as well, however, it is very stiff and perhaps a small amount of flex may be ok, it is not that large of a span.
Old 04-10-2008, 09:11 PM
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Default RE: KMP F-7F Tigercat

Hi Chasman and Drifter ---- I mailed your Center Section Hight strength aluminum tube and a bag of chopped carbon today. You should have the box in 2 days..

Col. Chuck Winter
Old 04-11-2008, 01:43 PM
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Default RE: KMP F-7F Tigercat

Hello Detleff,

Your T-Cat looks cool..., nice pictures.
I am stilll waiting for my Sierra gear ( already for 4 weeks now...)
How long did you have to wait???

I don't get a email reply as well from Darrell.....what is happening???

any one ????

Ton
Old 04-11-2008, 08:28 PM
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Default RE: KMP F-7F Tigercat

Wow I got my gear within days, but you are a little
farther away from the states
Old 04-14-2008, 01:41 AM
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Default RE: KMP F-7F Tigercat

Hi Ton,

my gears arrived in approx. 2 weeks.

Perfect service from Darell....

With emails sometime its difficult, as they sometimes disappear in the spam-folder...

Cheers, Detlef




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