warbirdmustang

My Feedback: (21)

Thanks for all the great info here, guys! I got one for Christmas! What a wife! I plan on powering mine with a JJ1400, and making many of the mods you guys have figured out on this thread. I can't wait to get it in the air.
Thanks,
Bryan

Boomerang1

http://www.btemodels.com/Downloads/R54Updt6.doc

is a link to the builders update for the Reaction 54. It shows the brake mounted outside of the wheel on the leg & notching the brake so it fits further on the axle towards the leg. These are all fitted to the noseleg.

Also, what you can do is solder some brass tube over the axle to extend it. Then drill your wheel out to suit. My Kavan brake had a big hole in it anyway & I had to sleeve the axle to get it to fit snug.

I have the smaller Bobcat with all the fuel in front of the CG. You can notice the change in CG in flight but it's not alarming. Just make sure you balance the model with an empty tank. I have seen it mentioned that you can heat some tanks with a heat gun to flex it up over the wing tube. - John.

Grodus

Flyguide,
I have 2 of f-120's and both of mine required the batts in the space behind the wing tube to get the proper cg. I bought one of the Kavan brakes and didnt use it because it is so heavy. I think you will be looking at adding a lot of weight to get the cg at 13" if you put that heavy brake on the nose wheel, unless you are using a p-80 or similar weight engine.
I made a tool for the forward wing bolts. it is simply a short hex head bit glued into a 1 X 1/2" piece of light ply. The light ply serves as a way to turn the bit. I also have one of the early kits (better) which did not have provisions for forward wing bolts. I didnt install any on the first kit and have had no problems.
Hope this helps,
Cody

joeflyer

My Feedback: (48)

The tank needs to sit on top of the wing tube in order to be centered on the CG. It's tight but that provides enough clearance to get to the wing bolts through the access hole. Since it fits in my truck with the wings on I never remove them anyway.

You should do a search in this thread, there are a number of postings on various tank alternatives. I used a heat gun to deform a 64 oz. juice bottle so that it fits over the CG. See the pictures I posted on page 22.

Joe

flyguide7

Thanks for your advise and help however if the CG is 1/2 inch forward of the main wing tube, this point leaves about 2" of space aft of the CG but the typical juice bottle is over 10" long. Are you guys using a 4" long fuel tank? Sorry to seem dense, but I dont see how I can center my tank over the CG unless I go with a 4" long tank and I really want to get this right.
Thanks again.

joeflyer

My Feedback: (48)

I guess you didn't bother reading some of the earlier postings. Perhaps I wasn't clear in my last post; one solution is to heat up the juice bottle and make it conform to the fuse so that it fits far enough back. See post #547 on page 22.
http://www.rcuniverse.com/forum/m_59...22/key_/tm.htm

Joe

flyguide7

Joe I am sorry I did not mean to sound like a smart _ss. That was not my intent. But looking at your set up it looks like your tank is longer than 4" long. (nice setup by the way). How long was your tank after your mod?

Hey and thanks for your responses as you can see you are the only one who took the time to respond to my questions.
Cheers
Ed

noray1

I had one of the early BVM Bobcats and the fuel tanks were located in the wings at the root and against the leading edge. All 2 leters were in front of the balance. I saw very little change in trim from take off too landing.
Ray

new2jets

i use a 2lt pop bottle yes there is a lot of fuel forward of c&g but does`nt seem to make any odds, just balance the model at 13" with uat full of fuel wacht my landing on you tube

http://uk.youtube.com/watch?v=GizfxuImc2k


To hold the wings on i cut the heads of the 6m/m wing bolts and drilled a hole through them and locktighted them in and screwed two ali blocks each side of the fuse inside with 6mm holes in to take the screws , and drilled & tapped these m6 at 90 deg to the 6 mm hole to take a m6 grub screw with a point on it which when the wing is on the grub
screw point lines up with the hole in the bolt sticking out of the wing and lockes it on only two 6mm hole in the bottom of the fus to stick the allen key throught works realy well and quick see photos on page 39.

joeflyer

My Feedback: (48)

Ed,

I didn't think you were being a smart a**. Maybe I'm too close to it, but I though it would be obvious from the pictures and description in the referenced post. Also if you read some of the early postings in this thread there are several different bottles and configurations that the guys were able to make work. I have used a 64 oz. Ocean Spray juice bottle before and it makes a good fuel tank, plus is the right size for a 14# class engine.

The bottle is about 10" long. I didn't change the length of the bottle, I changed its shape so that it would fit further back in the fuse. You'll notice that the fuse is tapered to the rear and narrower at the top. The plastic gets soft and deforms easily when heated. Heat up the bottom two corners of the bottle that will be facing up in the installed position with a heat gun and push them in using a piece of wood so that you don't burn yourself. When you get close to the right fit heat the corners up again and force it into the fuse a little further back than its final position. Let it cool for a few minutes and remove it. Make sure you pressure check it before and after installing the fittings.

Be careful not to apply too much heat or it might melt through. Take your time to get if just hot enough that you can collapse the corners. I was able to get the tank 4-5" further back by doing this. If you end up 1" or 2" in front of the CG that's not a big deal. 3 1/2 pounds of fuel will have a noticeable affect if it's much more than that. If you screw up you can always get another bottle at your local supermarket for about $4.00. Basically they're free after you drink the juice.

That's one way to do it. Use the search function in this thread and read all of the other tank postings for other ideas.

Good luck,
Joe

flyguide7

Thanks Guys for all your help. Your experience is priceless when it comes to avoiding costly mistakes that could dramatically shorten the lifespan of my falcon.

Grodus

Flyguide,
My #1 recommendation would be to shorten the mains by 1.5-2". I have one with the standard lenght struts and one with struts that are 1 3/4" shorter. the takeoff distance off grass is nearly cut in half with the shorter mains.
A 64 gulf lite charcoal lighter fluid bottle holds 72oz and fits with little mods, however, it developed a crack in about 50 flights and filled my airplane with fuel. Be careful on your tank selection.
I made a fiberglass conformal tank for my newest one. It holds 80oz and the front of the tank is behind the small forward wing tube. It has 2 cf pins on the bottom rear that fit into holes in the rear most former. The front of the tank is secured with a ply bracket that has holes for the forward wing tube to pass through. Removal would require the removal of the former just aft of the canopy opening. I can measure the foam plug that I used to form the tank if you are interested.

Also, when building, keep in mind it will tend to be nose heavy so plan your install with that in mind.

Cody

flyguide7

Cody how long are your mains now that you have shortened them? I ask because I am not using the stock struts. I went with the hobby City 2205s with spring loaded struts which has an overall length of 123mm or a little over 5".

Grodus

Ed,
Looks like mine are 4 5/8 from the center of the axle to the inboard part of the retract unit.
Cody

joeflyer

My Feedback: (48)

Cody,

Which struts are those, from Dreamworks or Digitec? Also how long is your nose strut?

Thanks,
Joe

Grodus

Joe,
They are the pro-lynx from Digitech. The nose strut is 5 5/16 or 137mm. I made new formers and set the nose gear retract rails about a half inch further into the fuse.

Cody

joeflyer

My Feedback: (48)

Thanks. What do you think of the Pro-lynx? I've been debating between getting a set of those or the Pro-links from Dreamworks? I have a set of Airpower retracts and BVM wheels/brakes and it seems like the Pro-lynx might be a better fit.

Joe

Grodus

Joe , I havent had any problems with them and they seem to have just the right amout of spring tension for the weight of the airframe. I went with these as opposed to the Dreamworks set because like you said, they fit the Airpower retracts. I'm sure the Dreamworks struts could be adapted to fit but, I am new to turbines and air retracts and I have discovered that it is difficult to find compatability with jet "stuff" , so I went with what I new would fit.
One thing is, the pick-up pin for the RA-250 nose retract is not long enough to allow for the steering arm and then go far enough into the strut. I used ejector pin stock to make a new one.
The Tam EDF brakes coupled with MPI wheels are thin enough to allow the wheel to fit into the wing without the strut sticking out of the wing when retracted. The Prolynx strut, Tam brake, MPI wheel and tire, weight less than the wheel and brake alone I use on my other falcon. The Tam EDF brake does not have enough power to lock-up but stops the airplane smoothly.

Cody

scalejet

My Feedback: (1)

I have be doing the reinforce the deck due to bigger turbine i got p-70 here a few pic

BaldEagel

Thought I would try a differnt approuch to getting the wing bolts in easier, with a lock nut counterbored into the root rib left just loose enough to turn with a ball hex head driver and put the T nut in the fus, if its good enough for the Composite Rookie then its good enough for the Falcon.

Mike

BaldEagel

Joe

I have a set of the Digitech Pro Lynx if you need any information please ask, but in any case the dims from the underside of the mounting flange to the axel CL is: 5.25" for the mains and 6.125 for the nose wheel.

Mike

flyguide7

Hey guys, has anybody had any problem with Tamjets? I placed an order on the 21st of December and paid for 2nd day air and.........nothing. No goods, payment went through. I sent them an email and no response. This is the first order I have placed with them and I am a little concerned. Anybody having a similar experience?

Woketman

My Feedback: (6)

Perhaps Tam is closed for Christmas.

akpepp

Must be closed for the Holidays. I have ordered from Tamjets many times and as far as I'm concerned he is the best. I have ordered stuff from him and got it in 3 days from California to South Carolina by USPS.

akpepp

I got the Pro-Linx with the 7/16" strut mount. I put them in Robart mains. Here is my setup with modified wheel cut-out.