RE: KMP F-7F Tigercat  
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RE: KMP F-7F Tigercat - 7/18/2008 6:11:58 AM   
camdyson



Posts: 828
Joined: 7/20/2005
From: Bairnsdale, AUSTRALIA
Status: offline
quote:

ORIGINAL: Blackwidow

Hmmmmm I'm not sure I understand the opposite aileron potential for the gyro during an engine out condition. Assuming both gyro's are in normal mode and no aileron inputs were given from the tranmistter why wouldn't the aileron gyro give control inputs to try to hold the wings level which is what you want regardless of the movement of the rudder? In full scale twins (aside from the mixture & prop controls) you identify the dead engine. push opposite rudder and raise the wing of the dead engine. Maybe I am missing something and if so I would really like to understand it better but I don't understand how the aileron gyro would drive the wings in the opposite direction. Thoughts?

Tom Rainwater
train@qualcomm.com


Yes, the aileron gyro WOULD attempt to level the wings. Unfortunately that's the problem!

If an aircraft is yawing/rolling to (say) the left, and you apply right aileron to correct, you are risking stalling the low/slow (remember engine out, and rotating around this tip) tip by adding a downward deflection of it's aileron. This just increases the angle-of-attack of the low tip, and can induce a tip stall and possibly the dreaded flick/death spiral.

It's far safer to ONLY use rudder to counter the yaw, and the wings should level themselves - you could dab the ailerons if needed but the gyro will just try to correct all the bank with opposite aileron.

Here's a link to the result of a tip stall on a nice twin:

http://www.youtube.com/watch?v=_T6HnDkigeo

Hope this explains it.

Cam

(in reply to Blackwidow)
       Post #: 1026

RE: KMP F-7F Tigercat - 7/18/2008 5:34:02 PM   
VKerster


 

Posts: 266
Joined: 12/14/2002
From: highland, MI, USA
Status: offline 		BLACKWIDOW, HERE'S THE PICS OF THE "COFFINS'..... THEY WORK EXTREMELY WELL. CUSTOM SIZED, BLOWN WITH PACKING FOAM. NOTE THE PVC FIELD STANDS. THE FUSE BOX IS 12"X83", AND THE WING BOX IS 33"X90".

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< Message edited by VKerster -- 7/18/2008 5:37:28 PM >

_____________________________

VKerster

(in reply to VKerster)
       Post #: 1027

RE: KMP F-7F Tigercat - 7/18/2008 9:12:04 PM   
CHARLES WINTER



Posts: 110
Joined: 1/29/2002
From: MERCED, CA, USA
Status: offline 		Hi Jack and Sierra Retract users. The length of my retract strut on my main wheel is 5 1/4 inches from Pivot point to bottom of strut upper casing. (see enclosed picture). Is this the length you all have? Seems too long to me! Jack - You mention a +/- dimension of 3 5/8 in. from top to top. I don't know where you are using that number? As I said in a previous post, I must put a 3/4 in. block under my main gear so during retraction the wheel just touches the nacelle fiberglass. If the strut was shorter, I could reduce the thickness of the 3/4 in. block. Thanks

Col. Chuck Winter

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(in reply to jbwilhelmi)
       Post #: 1028

RE: KMP F-7F Tigercat - 7/18/2008 9:42:14 PM   
jbwilhelmi


 

Posts: 51
Joined: 8/21/2005
From: Omaha, NE, USA
Status: offline 		Chuck

Am out of town until Sunday, will measure and repond then. The 3 5/8" dimension was fom the top of the former (the underside of the fiberglas nacalle) to the top of the 1/4" plate the landing ear spacer would sit on. All KMP parts.

Jack

(in reply to CHARLES WINTER)
       Post #: 1029

RE: KMP F-7F Tigercat - 7/20/2008 3:03:10 PM   
cordline


 

Posts: 14
Joined: 3/25/2007
From: Lathlain, AUSTRALIA
Status: online 		Hi further to tip stall,,,

This is a Tip Stall on take off..
The tail wheel is never lifted during the takeoff roll and the angle of attack is too high.
The Aircraft is taken airborne to soon without sufficient airspeed and the left wing is not flying.

www.youtube.com/watch?v=rlVpnCJAIkw&feature=related

(in reply to jbwilhelmi)
       Post #: 1030

RE: KMP F-7F Tigercat - 7/22/2008 10:28:47 AM   
cordline


 

Posts: 14
Joined: 3/25/2007
From: Lathlain, AUSTRALIA
Status: online 		And here is another one,, www.youtube.com/watch?v=vfb6aGQJ93o&feature=related

(in reply to cordline)
       Post #: 1031

RE: KMP F-7F Tigercat - 7/22/2008 8:02:48 PM   
chasrb



Posts: 953
Joined: 1/12/2003
From: Warrenton, VA, USA
Status: offline 		and on a happier note... Just weighed my TC and I was nicely surprised that it came in at 27.2 LBS!! The wing is 18.8 LBS and the fus is 8.4 LBS
This is dry weight. I was really thinking it would tip the scales at over 30 LBS.

The main components:

Twin Saito 170's
Two LiIon 5200's
One 3000 NiCd
Smatyfly power bus
all Hitec digitals...




_____________________________

Chasman

(in reply to cordline)
       Post #: 1032

RE: KMP F-7F Tigercat - 7/23/2008 2:21:25 AM   
chasrb



Posts: 953
Joined: 1/12/2003
From: Warrenton, VA, USA
Status: offline 		Took the Tigercat to the club meeting, and as was said before by Vkerster or Charles Winters It was a big hit! I fired up the 170's did a few taxi passes down the runway with calls of go faster from the other club members - we all know what can happen we too much speed is applied...unscheduled flight!

So anyway I am glad I am alomst done with the build, all I really have left now is the gear doors. I'd like to find some spring open hinges so I can make a reak simple door mechinism.

Later

_____________________________

Chasman

(in reply to chasrb)
       Post #: 1033

RE: KMP F-7F Tigercat - 7/23/2008 3:15:44 AM   
jbwilhelmi


 

Posts: 51
Joined: 8/21/2005
From: Omaha, NE, USA
Status: offline 		Chuck

I have same 5 1/4" dimension. KMP must have framed slightly different. Let me know if there are any other dimensions I can help with.
Jack


(in reply to CHARLES WINTER)
       Post #: 1034

RE: KMP F-7F Tigercat - 7/23/2008 4:50:25 PM   
P-51B



Posts: 6173
Joined: 10/11/2002
From: An Iceburg in, ANTARCTICA
Status: offline
quote:

ORIGINAL: chasrb

Took the Tigercat to the club meeting, and as was said before by Vkerster or Charles Winters It was a big hit! I fired up the 170's did a few taxi passes down the runway with calls of go faster from the other club members - we all know what can happen we too much speed is applied...unscheduled flight!

Later


I am pretty sure I was the loudest one calling for more speed, UNFORTUNATELY Chasrb maintained his composure and kept the kitty on the ground. ( )

Here is a video of the taxi test: http://www.rcuvideos.com/item/LTP0M8PLQVXN7JRN

It is my first video upload, and I appologize, but all I had with me was my older digital camera (5mp -low res by today's standards) and it formats to quicktime .

I have another one that is a cloesup of the static engine runnup, but it is over the RCU size limit...

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< Message edited by P-51B -- 7/23/2008 4:51:06 PM >

_____________________________

In order to think "outside the box", one must first accept there IS a box.

(in reply to chasrb)
       Post #: 1035

RE: KMP F-7F Tigercat - 7/23/2008 5:16:07 PM   
duber3



Posts: 132
Joined: 10/6/2005
From: QC, QC, CANADA
Status: offline 		Hi Charb!!

The sound of your saito is really impressive, nothing to compare of my 2 little G20

nice job

(in reply to chasrb)
       Post #: 1036

RE: KMP F-7F Tigercat - 7/24/2008 2:11:33 AM   
Streetfuz


 

Posts: 13
Joined: 3/29/2005
From: Bullhead City, AZ, USA
Status: offline 		Hi, I'm new to the forum but I have a question and could really use some suggestions. I have the KMP Tigercat and am about 95% finished with the build. The big problem is how to hinge the "Main" gear doors on the lastest KMP version. The older ones came with a slotted cover that just screwed on and then the main gear just went in and out of it, not too scale! Now the later ones have two gear doors per side. Problem now is the compond curves of the doors make impossible to get a hinge set up that works. I'm trying work with Robart hinges, they seem the best so far but are proving a "Bear" to install. Just using expoxy I don't beleive will stand the air pressure from landing or taking off. Any one out there that has built one of these and solved the proble?

The other problem which has been solved by friend and co-builder is the front nose gear and no way to keep it turning as it goes down it to and comes out of the nose. The factory forget to put a spring set up on it like all the other retrack systems out. What we did was design and duplicate a system very similar to Robart's nose wheel struct. Works just fine but someone that hasn't put too many "War Birds" like the Tri Gear F7F together will have a real problem. Anyone that needs further info on the nose gear, please contact me. This problem seems to be for all KMP Tri-Gear Gen II through Gen V, inculding non War Birds, any tri-gear system, either spring down air up or all air up/down has the same problem.

I understand that Andrew (KMP) is working on getting it solved but as of now it's still a problem. The F7F is a Great looking War Bird but once these problems are over come it should be a much better seller. We all know how money you put into a War Bird like this so I don't want anything to happen that could of/should of been corrected when they were designed. Tom

(in reply to wayneparrish)
       Post #: 1037

RE: KMP F-7F Tigercat - 7/24/2008 4:15:01 AM   
bignuts181


 

Posts: 143
Joined: 1/7/2008
From: melbournevictora, AUSTRALIA
Status: offline 		nice work chasrb your tiger cat sure sounds nice, whats your final all up weight??

cheers Rossco.

(in reply to Streetfuz)