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-   -   KMP F-7F Tigercat (https://www.rcuniverse.com/forum/twin-multi-engine-rc-aircraft-192/4814227-kmp-f-7f-tigercat.html)

dgiatr 08-09-2012 04:40 AM

RE: KMP F-7F Tigercat
 
1 Attachment(s)
7 times so far and tigercat flies really well..... so well that i nearly crashed it one week ago! i was at last turn before landing and i said to myself " this plane flies really nice almost like a single engine plane!" at that time i was having a really steep low speed right turn!, and i suddenly decided to fully open throttles from idle! ( i know all mistakes at the same time!!)...tigercat suddenly had that famous "spiral death" and it went down while spinning for about 4 or 5 turns ( i dont remember!!...its like a bad dream!), at about 3 metres from the ground i managed to stop it from spinning ( i cut throttles to idle and put down elevator, nothing else) and plane started flying level! but with the same direction to the wind, i didnt realised what really happened and i thought that i had lost one engine so i let it flying with zero throttles until it stalled at about one metre from the ground causing one leg and a small part of centre wing panel broken! i have twinsync on it and i am very happy with it but the conclusions is that you have to respect twin engine planes they are not single engine planes and you have to : open throttles really softly, take wide preferably left turns and pay attention to keep speed up specially while turning especially i would say that when plane speed is low (while turning or landing ) you have to be very carefull to sofly open throttles because every difference in engines rpm at that time can cause plane instability.

stoat 08-09-2012 12:32 PM

RE: KMP F-7F Tigercat
 
Hehe, yep a good leson learned! Fantastic that you got away with it without too much damage.
This is why I love twins - because they require more thinking while flying and demand a little respect it stops many people from trying them, so its that much cooler when one is flown.

And its a cool cool plane!

http://www.vintagewings.ca/VintageNe...Wagon-Rut.aspx

Cast your bo peeps over the link. A little inspiration for us all....

sabrejet 08-09-2012 02:21 PM

RE: KMP F-7F Tigercat
 
Have any of you T-CAT guys made this F7F electric powered? I have the KMP Tigercat also and not sure which way to go with powering it yet.

Any great comments would help!

Keith

stoat 08-09-2012 02:43 PM

RE: KMP F-7F Tigercat
 
A couple of the guys here have done elec versions. Nice but you dont get that great twin sound! Weight seems to be around the 30lb mark too.

ysolomon 08-09-2012 02:44 PM

RE: KMP F-7F Tigercat
 
I'm making it electric, but have been working on it on-and-off for a while now, so it will likely still be a while before I'm done.

dgiatr 08-14-2012 01:34 AM

RE: KMP F-7F Tigercat
 


ORIGINAL: dgiatr

7 times so far and tigercat flies really well..... so well that i nearly crashed it one week ago! i was at last turn before landing and i said to myself '' this plane flies really nice almost like a single engine plane!'' at that time i was having a really steep low speed right turn!, and i suddenly decided to fully open throttles from idle! ( i know all mistakes at the same time!!)...tigercat suddenly had that famous ''spiral death'' and it went down while spinning for about 4 or 5 turns ( i dont remember!!...its like a bad dream!), at about 3 metres from the ground i managed to stop it from spinning ( i cut throttles to idle and put down elevator, nothing else) and plane started flying level! but with the same direction to the wind, i didnt realised what really happened and i thought that i had lost one engine so i let it flying with zero throttles until it stalled at about one metre from the ground causing one leg and a small part of centre wing panel broken! i have twinsync on it and i am very happy with it but the conclusions is that you have to respect twin engine planes they are not single engine planes and you have to : open throttles really softly, take wide preferably left turns and pay attention to keep speed up specially while turning especially i would say that when plane speed is low (while turning or landing ) you have to be very carefull to sofly open throttles because every difference in engines rpm at that time can cause plane instability.
ok! after some wing and landing gear repairing tigercat is ready to fly again, with cowls on it that time, i will wait for a little because temp here is really high , i am thinking of flying it at the beginning of september.

dgiatr 08-29-2012 12:16 AM

RE: KMP F-7F Tigercat
 
a question for nitro or gas tigercat owners :
whats the maximun possible difference in r.p.m. between the two engines that you let your model fly;...say 500 rpm difference at 15-20%% throttlle travel is that acceptable or not;...i know that everything is relevant to speed that your models would have at that time so lets say that 500 rpm difference happens when model speed is low or while landing with full flaps at about ,say 1 metre from the ground

rcnut101 08-29-2012 07:40 AM

RE: KMP F-7F Tigercat
 
No More than 200 rpm!

stoat 08-29-2012 03:45 PM

RE: KMP F-7F Tigercat
 
Better still, nothing. More critical to have them matched at low rpm.

cordline 09-02-2012 02:05 AM

RE: KMP F-7F Tigercat
 
I have 20cc Zenoahs in mine and initialy tried a Twin Sync but i could not isolate RF problems so i gave up on it.
I put a Rate Gyro on the Rudder and any difference in RPM is not such an issue.

Cheers
Wayne

dgiatr 09-03-2012 04:50 AM

RE: KMP F-7F Tigercat
 
Thanks for the info!
i would like to ask those of you using twinsync ,whats the lower limit that you have set twinsync to engage , say from about 2700 rpm is that very low or not; if yes then whats the possibe problems that might have such a low setting; ( i mean to set twinsync to work from 2700 rpm and above), manual says something about that but to be honest i dont get it!...in my tx and with my own settings i get 2700 rpm after two clicks above idle ( i have high idle in case.....)
Thanks!

Ratus 10-01-2012 09:42 AM

RE: KMP F-7F Tigercat
 
Hello all,

First fly of my tigercat and 2 vidéo's.

[youtube]http://www.youtube.com/watch?v=atYZAlFfAdM&feature=relmfu[/youtube]
[youtube]http://www.youtube.com/watch?v=UEPcYIEY-R0&feature=g-all-u[/youtube]

Alain

Ron McGrath 10-02-2012 07:54 PM

RE: KMP F-7F Tigercat
 
What engines do you have in your TC?

Ratus 10-02-2012 10:32 PM

RE: KMP F-7F Tigercat
 
Hello Ron,

it's 2 91 4 stroke (P.H.) copy of OS. and 2 master airscrew propeller 13X8

Alain

Ratus 10-04-2012 12:07 AM

RE: KMP F-7F Tigercat
 

https://fbcdn-sphotos-h-a.akamaihd.n...35981252_n.jpg

70sflyer 12-08-2012 06:43 PM

RE: KMP F-7F Tigercat
 
Just received my f7f Tigercat,Fuselage has damage ,so I need to get that fixed.Will do electric,Im thinking 60 mtrs,2-80 amp ESC ,26s 5000 batts ,Let me know what you are doing.This big twin is going to be different than my other twins.

donddsms 01-04-2013 12:51 PM

RE: KMP F-7F Tigercat
 
Hello Airraptor,
I am doing this backwards! I received my Tigercat three weeks ago, along with ESM electric retracts, and NOW I just completed reading this thread that started years ago! I am truly greatful to all the hard work and documentation presented in this thread, and I can see this is going to be the longest and most difficult build I have ever attempted. I am wondering, are you satisfied with the retracts? I notice a lot of pilots seem to eventually switch to the Sierra retracts. Thanks. I will be checking back here frequently. This thread would make an excellent hard-bound edition!
Don

donddsms 01-04-2013 12:54 PM

RE: KMP F-7F Tigercat
 
I also understand there is a parallel tigercat build thread, but I have been unable to locate it. Can anyone give me a link to it?
Thanks.
Don

rlinus 01-04-2013 02:01 PM

RE: KMP F-7F Tigercat
 
I am in the same boat as you. I just got the plane about a month ago, didn't get the retracts yet. I haven't started building anything yet. Still deciding on which engine to use and how I'm going to do the retract doors, removable outer wing panels etc.. Think I'm going to go with an OS 120 4 stroke. I agree this one is going to take awhile. Keep posting!

Rocketman_ 01-04-2013 03:53 PM

RE: KMP F-7F Tigercat
 


ORIGINAL: donddsms

I also understand there is a parallel tigercat build thread, but I have been unable to locate it. Can anyone give me a link to it?
Thanks.
Don
Are you referring to the ASM F-7F Tigercat thread?

http://www.rcuniverse.com/forum/m_90...tm.htm#9096477

Ron McGrath 01-04-2013 08:59 PM

RE: KMP F-7F Tigercat
 
I have a set of OS 120 sp (super charged) 4 cycles that I was thinking if I got sick of the E setup I could put in my Tigercat but it would be a minimum of 3 less HP and that would make me sad. :(

tom_sandiego 01-04-2013 09:14 PM

RE: KMP F-7F Tigercat
 

ORIGINAL: rlinus

I am in the same boat as you. I just got the plane about a month ago, didn't get the retracts yet. I haven't started building anything yet. Still deciding on which engine to use and how I'm going to do the retract doors, removable outer wing panels etc.. Think I'm going to go with an OS 120 4 stroke. I agree this one is going to take awhile. Keep posting!

Call or email Lenny at [email protected] for the retracts, he custom made for my tigercat way better than Sierra retracts. You can see my photo in his website http://www.shindinmachine.com/pilotprojects2010.html.

and this one for 3 pieces wing http://www.rcuniverse.com/forum/m_86...tm.htm#8655593

Sundownee 01-05-2013 04:27 AM

RE: KMP F-7F Tigercat
 
Hi guys, I myself have been watching this thread for awhile also. I picked up a full composite kit last month from here NIB with full Sierra retract gear, wheels and struts. Going to use Saito 200R3 radials, already picked one from here the other day NIB.
RCU always has been a great place to shop to find things and save some money.
I believe this project is going to be a longer build myself. Still looking for other parts needed as servos and etc.
Might start a new thread on this build.
Keep the posts coming guys, lots of great ideas.

Paul Sousa

donddsms 01-06-2013 08:22 AM

RE: KMP F-7F Tigercat
 
Thanks all for the information. At the moment pondering engine choice. I wanted to emulate Col. Winter's efforts with Fuji 24's, but they have been out of production for awhile. CRJDriver (Chris) I think used Zenoah G20's and loved them? Pylon2 also used G20's with no nose weight. Grossy2 are you happy with the GR26i's? I have noticed positive references to DLE 20ei's also. At the moment I'm leaning towards the G20's, but thinking hard on the DLE 20s.
I am very much open to suggestions/advice. Thanks.
Don

rcnut101 01-06-2013 08:32 AM

RE: KMP F-7F Tigercat
 


ORIGINAL: donddsms

Thanks all for the information. At the moment pondering engine choice. I wanted to emulate Col. Winter's efforts with Fuji 24's, but they have been out of production for awhile. CRJDriver (Chris) I think used Zenoah G20's and loved them? Pylon2 also used G20's with no nose weight. Grossy2 are you happy with the GR26i's? I have noticed positive references to DLE 20ei's also. At the moment I'm leaning towards the G20's, but thinking hard on the DLE 20s.
I am very much open to suggestions/advice. Thanks.
Don

Either engine choice will be fine, My first one had G-20's and pulled good. I'm finishing my second one with G-26's. If I had it to do all over, I would have used big 4 stroke glow due to being a lighter setup. Keep the model as light as you can.


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