Byron Hellcat, need help
 

I just bought a Byron Hellcat from an estate sale, plane is more than 15 years old, lot of things have to be reworked or reenginnered:eek:. My problem is that the plane came without any documentation,[:o] I would need to know where is the CG located, I do not trust where is at right now. I am getting rid of the plastic prop set up and I am looking for a the prop hub adaptor for a 2 blade prop.

any feedback would be greatly appreciated.:D

Thanks

Popierre

RE: Byron Hellcat, need help
 

The CG is placed on a pre-determined spot on the fuselage during manufacture. Look to both fuselage sided just forward of the cockpit and around the center of the fuselage. You will see one small indentation on each side. These are the CG point. I have been flying my Byron Hellcat for about a year now and I used this CG marker. It is right on target. The Hellcat manual does not give a CG measurement. You are expected to use the indent marks. Good luck.

RE: Byron Hellcat, need help
 

I agree, the ident marks give that place a perfect CG. It is well behaved and ultra forgiving airplane. Get rid of the stock flap system, and if the builder used the stock nyrods on the elevators...lose them NOW!!!

RE: Byron Hellcat, need help
 

Thanks Guys.

I am reworking the plane a lot, got rid of the elevator set up, using 4-40 hardware all over, I saw the flaps system, in rework also. I changed the trottle linkage, working nice now.

next will be a 3 blade carbon prop.

how about flap deployement, how many degrees or inches ??

thanks again for the help.

Popierre

RE: Byron Hellcat, need help
 

I use around 80 degree down flown on landings. May sound like alot, but it works perfectly for my Cat. Landings are rock steady. On takeoff I dial in about 10 degrees. Flaps are not necessary on takeoff, but they sure keep things very easy. I agree, get rid of all nyrods and the ridiculous stock flap set up. For flaps, simply put servos out on each wing panel. This is the most reliable set up.

RE: Byron Hellcat, need help
 

Mark & Jeff -

I'm about half way through my Byron/Iron Bay Hellcat.

Can you go into a little more detail on how you re-engineered the elevator. Did you go to pushrods? Did it cause you to relocate the location of the servo?

I've seen other people warn about the flap design, too. Is the weak link the connection between the inboard and outboard flaps, or is it the whole thing?

I'm glad to see your info on the CG. There are so many dumb mistakes in the instructions I wanted to confirm the CG before it flies.

- Jay

RE: Byron Hellcat, need help
 

Jay,
I use one Hitec 615MG servo for each elevator half. These servos, as well as the rudder servo, retracts and kill switch servo are all located on a servo tray that I designed and is located directly under the belly pan opening. The elevators use carbon fiber rods and 4-40 harware.
I took one look at the flap design and asked myself one question . . . why? It is not only easier, but far more reliable to simply put one flap servo in each wing panel. I highly recommend doing that over the stock plan.
I love my Hellcat and you will too.
Give you guys a short war story on just how stable this model is (and by the way mine weighs in around 32 lbs). The last flight I had, I made my final approach all the way until touch down without my flaps deployed. I thought I hit the flap switch, but I did not get it all the way down. The Hellcat slowed to a crawl before she just started to wobble a bit. Then I realized my mistake, powered up and went around again. This time, the flaps were down and she slicked right in.
I included a few shots of the servo set up. Also one of the Cat stored away awaiting its next sortie.
Good luck and have fun.

RE: Byron Hellcat, need help
 

Thanks, Mark. Much appreciated, especially the photos. Your 'Cat looks sweet! Mine is going to be in tri color, too. I was at the Chino Planes of Fame airshow last weekend. Watching their Hellcat fly got me motivated to keep pressing on!

- Jay

RE: Byron Hellcat, need help
 

Everything that Mark said about the flaps and elevators is 100% accurate. Two servos for the flaps, and real pushrods on the elevators and go for it.

RE: Byron Hellcat, need help
 

FYI,
I finally put in a new tray per Mark's suggestion.
I had severe flutter on the elevator last year (when I bought it).
After opening up the bottom, I found a JR 507 moving both elevators with 1/8" plastic guide rods (I'm lucky I didn't lose her).

pic 1:
The new servo tray.
Six screws holding the tray in to triangle hardwood epoxied to the fuse (screws used in case I need to remove the tray: not too much room to work in there!).
I used two 133 oz servos for the elevators (that should do it!).
The rods are carbon fiber with 4/40 rod on each end.
The two new servos are on each side and I moved the rudder/tail wheel servo to the center.

RE: Byron Hellcat, need help
 

Got my maiden flight in after the servo updates.
She flew great. The G-62 is more than enough power.
I was flying 1/2-3/4 throttle.
The right stab came loose after the landing.
I had too much trim throttle and she kept on trucking into the grass and hit a small ditch and flipped over.
I'm glad the stab came loose: it didn't look like a good epoxy job and 'better on the ground than in the air'.

pic 1:
I used a carbon fiber tube that was a total 17" long.
7" into each stab and 3" for the fuse spacing.
I just drilled a hole in the external ply on the stab and fuse.
Since the stabs are foam core, I just pushed the CF tube into the foam.
There was a 12" X1/8" X1" piece of ply that cracked where the stab and fuse meet.
I just used the ply as a guide to push the tube in.
I leveled the stab and supported the tube so it would go in parallel.
I sanded the ends of the tube so it would kind of cut into the foam.
I drilled a bunch of holes in the fuse and stab where the two met so the epoxy could form tiny rivets.

pic 2:
Stab end.
The hole on the left is the one used.
The initial hole on the right had some brass tubing in the way which was probably for the pin hinges.

pic 3:
Ready to rock and roll!
It fit so tight that I didn't even have to touch up the paint on the top of the fuse.
The CF tube is very light but I used a lot of epoxy so I'll have to check the CG again.

RE: Byron Hellcat, need help
 

Looking good, Sam. You will have years of great warbird flying with that Hellcat. Great airplane.

RE: Byron Hellcat, need help
 

Don't see to many of these out at the field.
I love the profile of the hellcat.
It reminds of linebackers: they aren't pretty but, just looking at them, you know if you cross the line, you're dead meat.

RE: Byron Hellcat, need help
 

Anyone still flying their Hellcats? Im just getting ready to paint mine.

Charles

RE: Byron Hellcat, need help
 

I have a F-6F HELLCAT 90. It is an ARF. I was having trouble finding the CG also.It doesnt have it in the manual.The plane doesnt have the dimples in the side. I just started building the plane and noticed there wasnt no CG's. I was wondering if anyone could help me.

RE: Byron Hellcat, need help
 

Popierre,
Don't know if this helps but I just picked up a NIB Byron Hellcat. So of course I did a search on RCU. While perusing the manual I found a couple answers for questions you were asking. All answers are on pg 17 of the manual. CG is measured at 7 3/4" back from the nose ring face. Flaps are recommended at 40 deg. Elev 3/4" up and down. Ail 1" up and down. Rudder 1" each way from center. Weight is 22 - 24 lbs. The manual does mention that the indents are there to ease finding the CG. The manual also mentions to be sure and put the gear up when you check the CG. Also says to balance for a "slight nose down condition".

Jeff

RE: Byron Hellcat, need help
 

fyi,
I just went out and checked my CG.
My Byron hellcat is 5 3/4" back from the LE next to the fuse with gear up and upside down.
She a great flyer plus easy to fly.
I built a box over my engine to hold the extra weight.

RE: Byron Hellcat, need help
 

Sam,

My Hellcat came out at 25.5 lbs .... but I still need to add lead to the nose to get it to balance. I checked it and unfortunately I need to add almost 4 lbs. So mine, with fuel, is gonna be well over 30 lbs. Sure hope thats ok! Have you weighed yours yet? Just wondered since you said how well it flies.

Charles

RE: Byron Hellcat, need help
 

Charles,
I don't think you'll have any problem with the weight.
I wouldn't want a G-45 pulling it around.
I've got a G-62 in mine.
You might extend the engine out a little farther to help on weight.
Since there's no spinner, an extra wide gap in front of the cowl isn't going to be noticed.
I'm not sure what mine weighs: probably around 28 lbs.
I've seen lots of heavy warbirds fly with no problems.
Just make sure you have high oz torque servos (at least 94, I go with 133 with 6 volts).
Also, no floaters on landing: come in with flaps and fly her to the ground.
Here's video of me landing my spit:

http://www.rcuvideos.com/item/VSVT2H7ZH7Y5DT35


I guess I should mention taking off too: make sure you've got flying speed before giving up elevator.
You'll need 75-100' of high throttle before giving any up.
(That 100' isn't total length on the ground but after you've given it full throttle).
If you start to veer to the left or over compensate on the rudder and veer off to the right, shut her down and try again.
I'd rather 'look' like I'd don't know what I'm doing than take off too soon and 'prove' I don't know what I'm doing.
You can get away once in awhile taking off too soon but the balsa gods are waiting and, sooner or later, they'll win.
Too many pilots seem too quick to lift the plane off the runway before flying speed is attained and then want to get high at the risk of not having enough flying speed that you get at a low angle climb.
(when I mention plane, I'm talking about large warbirds only)
Here's the spit taking off:

http://www.rcuvideos.com/item/6VRHKB0W8Y9MDBFG

RE: Byron Hellcat, need help
 

Thanks for the info. Wow your runway seems so narrow and short. Guess Im spoiled where I fly! My Hellcat has a Brisson 4.2 ci (72 cc). Hopefully that should be enough power. Now I worry about my flaps. Hope they hold up. Maybe monday I will do the maiden flight.

Charles

RE: Byron Hellcat, need help
 

The runway is about 20' wide and 400' long, has a hill in the middle so if you are standing at the far side of one end, you can't see the other end and there's usually a 8-10 MPH wind coming at a 45 degree angle from your left shoulder.
One nice thing is, if you can fly here, you can fly anywhere.
Another nice thing is no trees and, except for a power plant about 1/4 mile away, it's all unrestricted.
Pictures showing looking east, west and north.
Of course the best part is: you never know what you'll see when you come out to fly on a weekend!

RE: Byron Hellcat, need help
 

Wow ... what a great group of planes! The guys flying there must have lots of experience flying off that runway. And yes ... after learning to take off and land from there you really could fly from anywhere. [&:] Some of those plane look like they would use nearly every inch of the runway.

Sam ... how did you do your flaps on the Hellcat? I have mine the way the instructions called for but Im not to thrilled with the setup.

Charles

RE: Byron Hellcat, need help
 

Sorry on the delay: didn't know you asked me a question plus I've been busy working on my new yellow P-38.
With the weight of mine, she gluides forever so I modified the flaps (some might say butcher!) to get more 'down' in them.
I bought the plane RTF but the flaps hinges were connected so the flaps would not fully deploy.
After re-hinging, the internal ball/socket control rod was binding so the flap would not come down.
The angle of the flap control horn was such that it would just sit there when the servo was thrown.
I left the internal horn on the flaps and added surface control horns (at least you can't see any bolts from the top!).
I then cut a hole in the bottom of the wing near the TE and ran a straight connection between the servo and control horn.
Not pretty but the dark blue hides it and I'd rather have a good flying warbird than a pretty one that I don't care to fly!

RE: Byron Hellcat, need help
 

Well ... yesterday I did the maiden flight! All balanced and fueled up it weighs 32 lbs. I couldnt believe it would actually get off the ground at that weight but WOW .... it flew great! After 10 minutes of flying I lowered the gear, came around base to final and dropped the flaps. There was no terrible or even noticable pitch changes with the flaps deployed. Flew her on down close to the runway, flared and she sank right in nicely for a great landing! Even though I had shaking hands and knees ... :) WHEW ... glad that flight is out of the way. Taking it back out again this Friday.

Charles