carmad_99

I ordered the Flying cat 71 jet model a while back. So far its a nice looking model and assembled ok. but now Iam down to installing the fuel tank. I can find nothing in the instructions about where it goes in the model. I can not find a place inside the model to mount it? Mabe a hint would help.I have the spitfire and the ultra biplane ,they are very nice to build and fly Thanks Skip

opjose

You want the stopper on the tank to face FORWARD.

The tank mounts in front of the engine in the fuselage... usually straddling the C.G. by some amount.

You can either stuff foam into the fuse and slide the tank in, then put additional foam to pad it into place... which some people do...

Though I don't recommend ...

Or you can make a retainer from small light ply pieces of wood.

I usually do the latter.

I glue foam between the ply and the tank ( on the wood side ) to prevent transmitted vibration, and to absorb shock.



BTW: Many ARF's leave this up to you. My H9 Funtana S90 came similiarly set up... no retention for the tank.

kid chuckles

The web site of Hanger 9 does not show a Funtana S90 or a Funtana 90 is this an old plane you have? I have the Funtana 100 and know of a 50 and a mini but have not seen a 90. Do you have a pic of the S90? I will look again and see if i just missed it. Sounds cool.

Carmad that is strange I have done lots of ARF"S never a JET one or ducted fan. Seems there would be a place for a fuel tank. But opJose is probabaly correct about this and you might just have to make the fuel tank work and either make a spot or a box of somekind. You might also and this is the way my Super Chipmunk from Nitro was Try silicone. On mine you just set it where it went and siliconed around it. Was very hard to get silicone in there but it did work. Maybe silicone it to the floor.

opjose

Yup: See: [link=http://www.rcuniverse.com/magazine/article_display.cfm?article_id=373]Funtana s90[/link]




There is indeed a place for the fuel tank, but there are no supports.


What is provided on the Jetcat, permits you to install the tank facing backward easily, with the stopper towards the rear, which of course is NOT what you want.

The Bobcat .50 and 1.20 is the same.

The Bobcat .25 is similiar but provides for both a tank and electric conversion.

kid chuckles

OP that is a cool looking plane for sure. I guess that is the first time i saw the 90. Thanks for the pic. and the link. Look good.
The Flycat he is talking there is not a place even made for it to go. Seems like he might just have to guess at best. Sure looks
like some place would be set aside for the tank to mount. OP knows more about there inventory than I so maybe he can help you
out.

carmad_99

has any one tried nitroplanes F-86D? it looks great, but a prop on a jet, I dont know how good it would fly. I am thinking about giving it a try.

Bluesangel

My Feedback: (34)

OK, on the Fly Cat, I have a 120 Two Stroke size engine looking for a home. The only problem is that I can't locate a pusher prop that fits the torque and dimensions needed. Am I missing something? I've even been looking towards the 3 blade pushers which is much worse on selection than anything else. HELP!

opjose

You can often use a larger sized 3 bladed pusher and cut/sand it down to the size you need.

SirHackEvil

Master Airscrew has a few 3 blade pusher props. I have one with a 90 2-stroke and I'm running a 11 x 7
3-blade on it. I just finished the plane but have not had it in the air yet. I have run the engine and was hitting
just under 12,000 rpm. with this set up. Master Airscrew has 12 x 6, 13 x 8, and 14 x 7 3-blade but I don't
think you'll get the 13 x 8 on the plane with out hitting the tail.

Bluesangel

My Feedback: (34)

WeEEEEEllllllllll......I kind of fudged the thrust line for the larger engine, so it is extremely possible for me to get a 13 inch prop on there. Right now I'm looking at taking a MAS 16X10 3 blade and cutting it down to 12-12.5 inches. It's now getting to where I need to prove a point. I was told that a small group of consults believe that if you cut the ends off of a "constant" pitch prop then you will lose efficiency because the actual thrust is at the tip of said prop. My belief is that if you had three numbers in the sizing of said prop (progressive pitch) then this would be true. Oh, and don't worry about the thrust line issue, I can always go back to the original mounting hole locations and work the smaller prop if it shows it is pulling to the canopy on the uplines and knife edges (if this thing can actually achieve a knife edge that it)

Knife Liddle

Anyone here flown the FlyCat at the suggested CG of 12" at the root?

Bluesangel

My Feedback: (34)

Don't do it!! Look up the manual at Kondor and you'll find them marking it at 9.6. I need a clarification. We just trashed one of two yesterday. I don't need that to happen again!

Knife Liddle

Yep, that`s what I thought. Sorry about your new plane. And thanks for finding a manual with the correct location in it.

I`ve written Nitroplanes on the RCGroups vendor page and told them they have a problem...and need to contact all customers who have purchased to warn them. Their response was not satifactory IMO. They said they`d have their manufacturers correct the problem on future planes.

I wonder how many other FlyCats have been wiped out on their first flight?

Oh well, I`m just one guy who shouted from a rooftop. I guess no one heard.

SirHackEvil

I would not use the 9.6" from the KMP web site. If you look the manual on their web site
it is for the Flycat-46 not the -71. I have one built, but have been trying check to see if the
12" is right. To balance at the location given I would have to add weight to the tail and from
what I hear with most pusher type aircraft you need to keep everything as far to the front as
possible. Don't want to re-kit on the first flight.

James

Knife Liddle

I`ll check the online manual, but it matches my calculations almost exactly. 9.6" works out to aprox 30% of the AMC. If you try first flights farther back than that, make sure to have a change of shorts in your pit box. Lee

Bluesangel

My Feedback: (34)

Good Catch on the size of airframe. At this point I'm ready to back up and punt. The only thing I have to go with are the wing calc numbers and refering to the "pictures" yes I said it..... pictures of both manuals. The .46 shows the CG point well in front of the wheels and wing tube and in the manual for the 71 it shows the CG point located right at the wheels and just in front of the wing tube. I'll bet I can fly this thing nose heavy better than I crashed it tail heavy...... If anyone has any better suggestion let's hear it.

Knife Liddle

You are right, the manual is for the smaller version. However the numbers still match up. Maybe it`s coincidence. Maybe they`ve miscalculated the CG on the smaller one too and it just happens to be about where the big FlyCat needs to balance.

It`s not exactly the same. The online instructions show 9.8" and I`m saying 9.6", but it is close.

I can assure you that the 9.6 mark will be flyable on the large Fly Cat. It may be a little nose heavy, but it`s always best to to error on the nose-heavy side.

If it doesn`t want to rotate, raise the nose as it sits on the ground. At 9.6" the cg is fairly far in front of the mains. Too far for easy rotation, so it may need the positive angle of attack to lift off.

VeeAte

I have a .46 sized one of these and have a couple of questions.

Do I need to have any right or down thrust? Or left and up seeing as its a pusher?

I noticed on the 46 size the rear of the engine mount has been cut on an angle. Guessing I should follow this?

As I cant redrill or shim the mounts in any way I want to get this right from the start. (46 has wooden beams sticking out the back instead of a firewall to mount the engine on)

peterbrown

Hi Guys.
I am in U.K. and have a Flycat 46 purchased from Ashford Models but with no identification as to the actual manufacturer.

The instructions do indicate a C of G position 9.8" back from L.E. but they also clearly indicate the fuel tank installed the wrong way round (i.e the clunk is facing forewards and the stopper backwards)
so one wonders about their competence.

I am fortunate to posess a Laser 70 fourstroke which is set up to run in reverse so I don't need pusher props.

So far after 4-flights the power /weight ratio is good and the model flies well untill you try to land it.

Every landing so far has ended in a "Dutch Roll" i.e. the wings wobble in violent left and right banks and I am lucky that so far the model has survived.

I contacted Ashford Models who first of all acknowledged that I was not the only Flycat 46 owner with this problem but that it did not occur on the larger 71 model.

Their first suggestion was to increase the rear fin area which I have done but it has made no difference at all.

They have now referred the matter back to the manufacturers but so far no reply is forthcoming.

It would be interesting to know if anyone else has come accros this problem and more important. "What is the Cure?"

Failing all else I will move the C of G foreward.

Regards. peterbrown England U.K.

VeeAte

Hi Peter Brown.

There is a thread on this issue here on RCU : http://www.rcuniverse.com/forum/m_5750756/tm.htm

They did as you have done and increased the vertical stabiliser surface and they also added area to the fins on the wing tips.

I am about to do this exact modification on mine.
Do you have a picture of how much area you added?
There are some pics on the thread above on how those guys solved the problem. Also some video of before and after.

I think this plane will always have this problem to a small degree at least. Very short coupled and nowhere to put a large practical amount of surface area. Without the plane looking silly anyway.

peterbrown

Hi VeeAte

Thanks a bundle.I owe you a great debt of gratitude.

I have read through the thread you gave me and it would seem all my answers are there

I will try the extra bits on the finlets and add some lead and then try again.

I placed exra balsa on the fin trailing edge where the rudder would be if it had one

I then added a further 1" below the fin cut out and carved a slot in it for the prop to go through.

I'm sorry that My attempts to transfer photos on R.C. Universe never seem to work.

Thanks again I will keep in touch on this thread or the other one. peterbrown.

opjose

You are effectively bringing the plane in TOO slowly.

You do not need the winglets and fin extensions.

The problem is that the plane develops a good amount of lift ( which is normally a good thing ) so as we attempt to land it, we let it get too slow, as we await for it to start decending.

We get "programmed" to do this by normal tractor planes with straighter wings, where this is the norm.

However if we don't let it get slow, the plane will seem to float far too much and you may miss the landing area altogether.

So how do you solve the problem?

In a word, "Spoilerons".

Spoilerons KILL lift ( unlike flaperons ), this increases the decent rate of the plane, but lets you keep the speed up higher so the wing does not stall.

You need to add about 1/8" to 1/4" of up spoileron deflection when you have the spoilerons activated. This will do the trick.

The spoilerons will also help let you do slightly nose high landings, further helping to slow the plane down once it touches down.

VeeAte

Thanks for the info opjose.

The problem with this plane is it does the tail wobble thing at high speed as well. After coming out of a banked turn when you bring the plane to level flight it will shake the tail. Slight gusts of wind will make it do it as well.

I think because most of the vertical surface area is up high the plane itself kind of pendulum's underneath the tail.

Think of a leaf falling to the earth swaying from side to side in a u shape as it falls. Thats the motion the rear of the plane is doing.

I am no expert on these things however. And could be way off

opjose

Yeah I've observed the "wiggle" too.

This is different than the wing drop on landings however.

VeeAte

Ok cool.
Thanks

Will differential on the ailerons help this plane at all?