RCISFUN

My Feedback: (44)

+1

ela

The Carf tank is working perfect for me with a brass tube in the middle. I use only the clunk in the tank and a filt clunk in the hopper. No problems in 170 flghts :-) I visit our frends in Ringebu RC from time to, its not only madness that is going on there :-) The place is famous for different model unfriendly things, like "magneting trees" so its good to keep the speed up ! He he..

http://www.youtube.com/watch?feature...&v=P36IB7r15ws

husafreak

My Feedback: (3)

Thanks for the inspirational post Ela! I must say that I think I made the right decision going with this CARF Hawk. I have watched a hundred videos at least before and after making the purchase and I still get most excited to see the Hawk fly. Yours is especially nice with the Swedish colors and the lights, high energy flying, and all those trees in the background!

fireblade5437

Finally starting to look how i want it to look!

Not easy getting the decals on but a bit of patience works wonders!

Hoping to get the back end sprayed in colour this weekend..

Alan

Note the green tubular greenhouse, theses are perfect for a spray booth set up as they retain the heat and even better they are not expensive. Paid £50.00 off web, currently £64.00 make sure you go for the ones with 25mm tubing as they will take the weight of the fuselage for hanging etc stops all the bugs and flies but have hung up a fly trapper to get the odd blighter also remember to use full air fed mask when spraying inside the 'booth'

Size is 4m x 2m x 2m

kev-o

My Feedback: (1)

I get mine next weekend can hardly wait , just need to install the Titan I have for it and program dx18 and its ready to go.

fireblade5437

You will like!

Which scheme did you go with?

Alan

kev-o

My Feedback: (1)

All black with roundel in middle Chris Hammond built it and needs to thin the fleet a bit so its coming to a new hangar with me. Should compliment my ct114 well I think.

Dave Wilshere

Rocket ship with a Titan! Even my P-120SX version has plenty of vertical punch!

Dave

kev-o

My Feedback: (1)

It's what I had available so that's what she gets plus we fly occasionally at 4-5000 ft asl so the extra jam will help there. I know how to exercise the left stick I flew my toot about 1/2-2/3 most of the flight unlike our #3 bird here I have a 120se in an élan but I still like flying it. But who knows this could become the new grass bird.

Kevin

Dave Wilshere

Kevin...cool, throttle stick controls the power, not the manufacturer figues ;-)

Dave

kev-o

My Feedback: (1)

Ya I know it had a rhino in it so at least I'm putting the right brand in it and a lil less push

fireblade5437

Well the weather here in the UK was windy and wet yesterday and no way could I paint the rear of the Hawk but today blue sky and sun :-)
Heated up the 'booth' with infra red and got temperature up to around 40deg C the 2k I am using can be baked at 60deg C for 30min

Alan

husafreak

My Feedback: (3)

I have a question about the turbine mounting location. The manual says to put the end of the turbine, the back end of the turbine tailcone, 25mm from the CF bellmouth/S.S. exhaust tube joint. Since the turbine tailcone on my Cheetah is 40mm long and the CF bellmouth is 70mm deep this puts the back of my Cheetah's turbine body 5mm into the bellmouth. To me it just appears the he turbine is "choking" the bellmouth. Looking at the pics in the manual it just looks like my Cheetah is too far back in this location. In the manual the Jetcat main body is clearly not protruding into the bellmouth. The Jetcat turbine tailcone and body may be much longer than my Cheetah. But it is my first jet so I could be wrong...

husafreak

My Feedback: (3)

So I continued my investigation and spent a long time reading the thread and looking at pics. One thing I found out is the Jetcat is much larger than the Cheetah. The Jetcat is 0.31" larger in diameter but it is over 3" (75mm) longer! So at least I see why the Cheetah sits so much farther aft of the bulkhead than the Jetcat. I have elected to move the Cheetah to a position where the turbine tailcone is about 35mm ahead of the CF bellmouth to SS tube joint line. This moves the main body of the Cheetah turbine 5mm ahead of the bellmouth opening. I hope that will be a good position.

husafreak

My Feedback: (3)

Here is a picture of the Cheetah in this position.

husafreak

My Feedback: (3)

BTW I just got a "rule of thumb" from my buddy Jack D. via his Dad, 3/4" is the sweet spot to have the turbine tailcone from the pipe. If we define "the pipe" as being the smallest diameter in the transition from the bellmouth to the SS section of the pipe then the CARF manual actually approximates that. If I subtract the approx. 10mm overlap of the CF bellmouth into the pipe that leaves 15mm from the smallest diameter of the bellmouth to the turbine tailcone which is pretty close to 3/4". JUST AS STATED IN THE MANUAL Because of the geometry of my Cheetah this will put the turbine core into the bellmouth opening but apparently the CARF bellmouth is a big thing and there will still be plenty of airflow around into the pipe. I was instructed that the critical dimension is from the tailcone to the corner where the bellmouth transitions to the straight pipe. . It will just look way different on my install than a Jetcat install. To do this I will be moving the Cheetah another 10mm rearward from the position pictured above. Oh well, it is one thing to read and follow instructions, another to understand what is going on... Big thanks to Jack and Sr.

ela

..and if you want the most neutral behaviour in flight you should move the engine to the other side of the rails. So that the thrust line will be more down. Check for clearance in the tailsection, elevator servo plate. But no worries if you do it like you have.

Dave Wilshere

Each turbine has a different need on tailpipe (turbine) to tail tube gap. Largest gap without turbulence is best.

I was going to post what Ela said, I guess the mount you have is mid turbine and not off-set like the jetCat. Get the turbine as high in the fuselage as you can (tailpipe to elevator servo plate dictates this) On my original (manual aeroplane) the elevator servo mounting plate is 10mm lower, so I had to pack the turbine off the rails to get the turbine and tube lined up. My model climbs at full throttle and I run a throttle-elevator mix. For production kits I had the elevator plate raised.

Flying yesterday

afterburner

My Feedback: (18)

I just got back yesterday from the First in Flight jet rally in North Carolina and managed to get in a good number of flights on the Hawk and noticed more of a pitch up at full throttle than I have since the maiden and susequent flights. Probably because of having six jets up together and focusing on maintaining consistent altitudes made it more noticable. I have a Cheetah in there like husafreak and am debating whether to raise the engine in the fuse above the rails(when the fuse is upright) and adjusting the pipe or putting in a elevator/throttle mix.

Husa, I seem to remember contacting Eric Clapp at JC about the mounting orientation of the kerostart Cheetah and he told me that the engine should have the lettering facing up for starting. You may want to contact him to to confirm before changing yours. If it's a gas start, I don't think it matters but kerostart is different I think.

Marty

luv2flyrc

My Feedback: (6)

I've flown my Hawk with both a Cheetah and a P-120sx. I use a down elevator to throttle mix to keep it from climbing at higher power settings. You need about 3- 4% with the Jetcat, about 6-7% with the Cheetah as the jet will fly a lot faster with the Cheetah.

I have both engines mounted in the usual configuration ( bottom of rails when plane is up right) so, techically, they are both mounted "upside down" ie. Cheetah with name plate on bottom and no problems starting ever.

Mike

afterburner

My Feedback: (18)

Good info Mike. The mix is obviously an easier way to go. Do you remember at what throttle position you started bringing the elevator mix in?

Good info also on the engine orientation. I know I asked Eric but whatever works. Thanks.

Marty

ela

If you go for the mixing you might consider activating it with the gear up switch. Needless to say why .. Also remember if you go for a slow by and suddenly goes full throttle your hawk will pitch down :-) It isn't the thrust that puts the nose up, its the speed. Lots of things to play with on our radios. I have a 4 sec delay on the down mix. That makes the plane achive speed before the down mix goes active.

Well. The best approach is to find the correct thrust line but mixing is more fun

afterburner

My Feedback: (18)

Yes, I was thinking that for say a missed or bad landing approach it could get ugly when punching the throttle and getting immediate down elevator. I might go for moving the engine/pipe first and see how it goes.

Marty

Zetti

Dave, what is the minimum distance between the tailpipe and the elevator servo plate? Is it okay, if the tailpipe sits on the rear former of the servo plate construction, or should there be a minimum gap?
I have fixed my turbine mount below the rails which gives an perfect alignment of the turbine and the tube (sitting on the former) with the thrust line going through the middle exactly (measured with a laser).

Stephan

luv2flyrc

My Feedback: (6)

The mix is so small you won't notice it, it's not like slamming the throttle stick is going to slam your elevator down. There's probably about 1/8" movement of the elevator between idle and full bore. If there's any pitch change at all , you'd probably compensate for it with the elevator stick and not even realize it.

Mike