RichardGee

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The good news... and bad news...[&o]

My Gee Bee weighs in at 32 pounds dry. This will increase a bit with the addition of pants and spats, but not by much.

The Bad News - it balances at 100mm from LE. This equates to 23.5% of chord.
Shown perched on my modified EZ Balancer, the scales (and balancer) DO NOT LIE.

On BOTH model and full scale, the ideal balance point is determined to be 18% of chord. This equates to 75mm back from LE.

Correction will require re-arranging a number of components inside the aircraft.

I had organized internals as instructed in manual and utilized DA 150 (notice cooling baffling built into cowl which also added nose weight). However, plane is still tail heavy (I worried about and suspected this as plane came together, so it is not terribly surprising[:-]).

I could omit pilot bust to help balance, but HOW can a Gee Bee fly w/o a pilot!!![8D]

Fuel and smoke tanks are right on CG so filling should have little to no effect.

Those of you using lighter engines, BEWARE!![X(]

RichardGee

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FLYING WIRES -

First, I IGNORED the manual's stated lengths and opted to determine correct lengths on my own using good kite string. I found actual lengths to be different than those stated in manual, but could not recall for you what the actual lengths should be - this will likely vary from model to model due to production tolerances and where each modeler locates the mounting holes in wings and fuselage.

I wrote down the EXACT required lengths - HOLE TO HOLE - and determined how to chop up flying wires accordingly. You will be cutting the 4 flying wires into 2 sections each, creating 8 separate flying wires.

Obviously, one end of the SS flying wire will have the forged threaded end, and the other end will require you to SILVER SOLDER a brass fitting that has been flattened, drilled, and bent to conform to mounting dimensions.

Proper soldering requires a VERY POWERFUL soldering iron or brazing torch, good flux and Silver Solder.

As the instructions state, "The flying wires are what HOLD YOUR GEE BEE TOGETHER IN FLIGHT" There can be NO COMPROMISES in properly constructing the flying wires.

I used a grinding wheel to fully rough up the soldered end of the SS wire before soldering. I also cleaned with lacquer thinner. Once constructed and mounted.....
The entire affair is tightened via the flying wire "cables" that go from inner gear mounts to bottom of fuselage. Once tightened, you can actually pluck the lower cables and they will 'sing' - Anything less than this, and you are asking for an in-flight failure OR a ground loop and flip over due to wobbly gear.

I have not yet flown this R2, but DO have experience flying a quarter scale R2.
ROCK SOLID LANDING GEAR are integral to landing successes.

PTS

My Feedback: (153)

Thanks for the explanation! On we go . . .

dwr

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Richard, your GB came in light. Hope you can move enough so you don't add weight. Mine should be about 33lbs. See post 188. I put the tank on the firewall like Jim did and everything else I could.
even the rudder servo is up there. The 3W100 is heavier than a DA 100 so that helped too. I am getting close but looks like I won't maiden till after a short trip up north. Should be ready about Aug 1st tho. DWR.

RichardGee

My Feedback: (156)

Right from the start, I was a little wary about locating rudder and elevator servos and Rx all the way aft, but that is where the instructions (and mounting parts) dictated. It also seemed the Fults "tail wheel" (modified from nose wheel unit), although sturdy, was on the heavy side. I still have not added TW fairing, but it should be extremely light.
I have yet to add canopy clear plastic, but again, should not affect balance much.

All during the construction process I kept lifting tail and wondering how in the world I was going to make the thing balance, even with a DA150 in the nose...

Have you balanced yours yet with the 3W? All OK?

I am in the process of mounting all batteries and voltage regulator on back of firewall. Will recheck balance after that. If need be, I will add an another battery pack or just switch to larger (4300 instead of 2200 Lipo's). I don't really like the idea of on-board RC gear being anywhere near engine or ignition, but I have no choice. Hopefully, my trusty Futaba PCM Rx will reject any noise...

Will provide update and pix when I have them.

dwr

My Feedback: (1)

Richard, balance was 75 MM with 1 1/2 lbs balast at dummy engine location. I have three 2600 mah li-ions at the firewall. PCM reciever is on the bottom of fuse just forward of the side door.
I had all components and pilot in the fuse at approximate locations when I balanced it. I'll balance again when everything is installed permanently. Right now fighting with the canopy. DWR.

BigProp

My Feedback: (32)

Well, in reading this thread, you guys have inspired me. I placed my order for a C-ARF GEE BEE today. I will be using a 3W 120 B2 for my power plant.
I am a novice builder, so any tips or tricks that you could pass along would be greatly appreciated. Looking forward to getting it built!

-Gio

RichardGee

My Feedback: (156)

DWR,

Well, it's back to the drawing board for me and this #@%&$@@!!! Gee Bee[>:]. It's going to require 2.5 pounds on the firewall/dome to get it to balance at 75mm from LE... and this is after mounting Rx and ignition batteries, ignition and voltage regulators on the back of engine dome, adding cowl baffles and engine dome reinforcement !!![:@]

Had I known this was going to be the case with CG, I NEVER would have installed the radio tray and servos where recommended in the 'manual'

This is quite disappointing, I must say, and baffling since I pretty much followed the instructions (as poor as they are) to the letter and, of course, have a DA150 on the nose.

I found that just a Great Planes pilot bust makes a HUGE difference in CG, but cannot possibly imagine the plane w/o a pilot in the cockpit.

My next steps will be to substitute 6 cell 7.2v NiCads (RC CAR style batteries) for the LiPos. These are heavy monsters that will deliver more than enough power, while also serving a useful purpose - nose weight.

I believe I will also need to move at least the rudder servo and Rx and the piezo gyro WAY forward - which entails remaking all my servo extensions, rudder pull/pull, TW control and all the various cable anchors I have installed... WHAT A MAJOR PAIN!!!!

I could also drill some lightening holes in the rudder front (inside fuse)...

Not sure how this happened... makes me wonder if the manufacture of my particular Gee Bee resulted in heavy aft end fuse and other components...[]

dirtydingus

Hey DWR,

Don't get discouraged. First contact Aircraft International they make foam pilots that look good and are weightless. On the issue of nose weight, if you fill the inside cowl leading edge lip with the smallest buckshot that you can get, and then pour in epoxy, that will put the weight much further forward than putting it on the dome. 2 lbs. on the dome would equate to less than 1 lb. in the cowl leading edge. Also, the wood I added to hold the baffling in place is 7-ply 5/16 birch-ply, more weight in the right place. This way the baffles are screwed in place after the cowl is on, giving full access to the motor and cowl bolts. I think these simple things should put you in CG ballpark.

RichardGee

My Feedback: (156)

THANKS for the suggestions.

I will very likely arrive at some combination of additional weight, batteries and equipment shifting to arrive at the correct CG.

I am not discouraged, just a little T'd off at CompARF's sub-standard instructions...

I WILL forge ahead as this airplane is simply my all-time favorite.

dwr

My Feedback: (1)

Hey Jim, this time Richard is doing the cussing instead of me. I am still *****ing a little but at least I can smell the finish line. It is amazing how bad the instructions are. My copy says they are temporary but I think they have been that way for years. More evidence CA lost interest in this airplane long ago. Jim did you get your engine back in yet? Richard, I agree about the pilot, gotta be there for those low flybys. DWR.

Gio, welcome to the group. If you have read the entire thread and still bought the beast then you certainly belong in this looney bin. DWR.

BigProp

My Feedback: (32)

Has anyone made up a "laundry list" of extra parts to buy for this plane? I am trying to go through all the control surfaces and see what I should be shopping for that was not included in the small hardware bag that came with the "kit". Any help would be appreciated. Thanks!

-Gio

dwr

My Feedback: (1)

Gio, didn't make a list. I think everyone pretty much uses the heavy airplane hardware they have experience with.

Well I'm puttin on the Kirby Graphics set. Finally got to the fun part. Will be up north a week. Should be ready to maiden a week or so after I get back, approx Aug. 1. DWR.

RichardGee

My Feedback: (156)

GB Gents:

Still waiting for my heavy 6 cell 4000 mah battery packs to be available so that I can balance my GeeBee. These will be used in place of the Lithiom batteries I had originally planned to use, thus, I can leave in place voltage regulators, et, al. Not sure if these will do the trick or if rudder servo will need to be relocated way forward. Won't know for sure until I get packs installed and this porker back up on the balancer.

One of the contributors commented that I had used ball links on the CompARF phenolic control horns - which is a big CompARF NO-NO. I concured that indeed, CARF instructions for their large IMAC planes do very clearly state these are not to be used. As such, I switched back to clevises on the GeeBee.

Just want to state for the record that my 2.6M CARF Extra uses ball links on all its phenolic control horns.... I know, I know, I DID NOT READ THEIR WARNINGS and only went back and did so after some 40 flights on the Extra. As recently as 2 weeks ago, a top 3D flyer put my Extra through a routine that subjected it to more wear and tear than all of my 40 flights, COMBINED - including full throttle blenders and blinding snaps. Happy to report, not a single failure of any kind.

Soooo, not sure why CARF is so adamant about not using ball links.... they seem to work great on my 100cc Extra and, in my never to humble opinion, are SUPERIOR to a clevis as a precision control connection.

Flyjets

My Feedback: (51)

RichardGee

Just for the record when doing a full power blender u are stressing the Fuselage. If done aggressive enough or repeatedly you will very likely cause a structural failure. I just witnessed a CARF 2.6m Extra flown locally be destroyed by this very maneuver.

I do these on planes I don't really care about.

Ian

dwr

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Well the decals are on. Everything has been double checked and buttoned up. Tomorrow I will recheck the CG. Then the only thing left to do will be to fly it. Most likely that will be next monday.
I'll let everyone know how that goes. DWR.

RichardGee

My Feedback: (156)

BEST OF LUCK!
I have been side-tracked on another project that will be completed by Friday, then it's back to the R2.

...Will be waiting with fingers crossed for a (great) flight report!!!

dirtydingus

DWR,
Sounds great. We are a very small goup of people,(Comp Arf Gee Bee flyers) so when someone else is getting ready to join the ranks it makes it that much more exciting. If I could give any last minute advice, I would say; Just remember it has the glide ratio of an overweight, stubby winged biplane. And the most important thing I have learned in 111 flights is (GO AROUND). Adding power to try and fix a bad aproach in this plane is suicide. Both times mine ended up on its back, could have been avoided by a go-around. Other than that it is a great flyer. Can't wait for your flight review.

dwr

My Feedback: (1)

Thanks for the encouraging words guys. I have already started to work on getting myself in the zone for the first flight. Have already packed an extra set of skivvies in my flight gear. Have been flying my P47 balls to the wall lately and wheeling it on a little hot. But with the GB "look ma no flaps!" I'll be praying for a steady 10 knot breeze right down the runway but that does not happen at our field this time of year. Most likely it will be close to dead calm at 9 a.m.

After I get the beast in the air and get it trimmed I will likely spend a lot of time in the landing pattern checking the sink rate with plenty of air under it. Hey it can't be any harder to handle than the GP GB. And most likely easier. I have found the bigger they are the better they fly......IF you stay inside the envelope.

Jim, thanks for the input. Anything else you might think of between now and monday don't hesitate to add. I land the P47 by setting up a shallow glide slope using about two or three clicks above idle and just fly it on to the strip. It only takes a frog hair of flair. How are you doing your approahes with the GB?.

RichardGee

My Feedback: (156)

DWR,

As a guy who successfully flew (and landed) a scratch built 25% Gee Bee R2 many times, I want to say you are doing EXACTLY the correct thing, practicing with a warbird; hot landings; no flaps.

I did PRECISELY the same thing in preparation for my R2 maiden many moons ago, and it helped immensely, as I greased both landings (yes, on two flights)

I spent a couple hours at the field the day before the R2 maiden, landing my plane VERY hot, over and over. It must have helped because after my maiden plus one, my Gee Bee success began to diminish[&o]
...or maybe I just got complacent[]

Put the hammer down on your JUG, and the Gee Bee should be no problem... just don't do what I did and get complacent[X(]

Can't wait to hear your flight report(s)

ALL THE BEST!!!

GEE BEE's RULE!!!!!!!

RichardGee

My Feedback: (156)

Just another update on my R2 project - specifically, weight and balance:
I finally acquired two 6 cell, 4000 mah NiMH packs and have built battery boxes on back of engine dome to accomodate. (see picture)

Starting from right, 42% Products 10amp 6 v regulator; 4000 mah 7.2 v airborne battery (in box); DA 150 ignition; 4000 mah 7.2 v ignition battery (in box); 42% Products Opto-Kill engine kill.
Ignition voltage regulator (42% Products 1.5amp voltage reg.) is inside fuselage on tank tray.

If this 2 pounds of batteries does not solve my balance problem, I will have to move my rudder servo forward [], resulting in further delays before MAIDEN FLIGHT!

Word to the wise - IGNORE equipment placement instructions (and included tray) and install equipment expecting to be tail heavy!![:@]

dwr

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Well our field hasn't been cut due to lots of rain so right now am shooting for Wednesdayfor the first flight. Realized that this little piggy is hard to handle getting it from shop to vehicle so made some ramps. I plan to wheel it around rather than carry it from the back of the SUV into the garage. DWR.

RichardGee

My Feedback: (156)

BEST OF LUCK ON WEDNESDAY.

I found that my beheamoth batteries on back of engine dome moved CG forward about 6mm. Better, but still not at 75mm from LE. This is truly frustrating!!!

I have now resorted to removing rudder and cutting large lightening holes in rudder front balsa face and will also have to move rudder servo FAR forward to achieve proper CG. I also found that glue joints inside rudder were horrible - composed of the "cake frosting" CARF used elsewhere in the model and not at all well adhered. I mixed up some epoxy and microballoons and glued.

Word to the wise for anyone building this plane - IF YOU INTEND TO ACHIEVE CG AT 75MM FROM WING LE, DO NOT INSTALL THE RADIO TRAY AS INSTRUCTED IN REAR OF FUSELAGE. ALSO, ELEVATOR SERVOS SHOULD PROBABLY BE INSTALLED FAR FORWARD OF RECOMMEDED LOCATION.

dwr

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Well OK, i'm done cussing this plane because it flys GREAT! The first flight did take a bunch of up trim on the elevator but none on ailerons or rudder. The recommended throws worked well. I used reduced rudder throws at 25mm as has been discussed. I used -50% exponential which is slightly more than I use on arobatic planes. The plane tracked well. I was suprized how stable it was when I slowed it down and when stalled it stayed level and just dropped the nose.

After my knees quit knocking I made some high speed passes. As luck would have it one of our club members brought his radar gun and clocked it at 100mph. I think I was going slightly down hill at the time. Next it was time to get into the landing pattern and do some approaches. I quickly found that when you pull the throttle all the way back while in your approach with the airplane already slowed down this airplane sinks like a stone. Right now! But it responds instantly when you add some throttle. I went around a few times until everthing looked right then wheeled it on with no problem. Back in one piece. Alright!

The second flight was great. It takes very little rudder input to keep it straight on takeoff so I guess that means the recommended throttle/rudder mix works. I found myself throttling back in the turns after full throttle passes so the thing wouldn't get too far out. Slooooow rolls take very minor inputs. This is going to be a fun airplane. It sure is nice when everything goes well on a first flight day.
It was nice using an engine that I already had adjusted and had many flights on in another airplane. So the engine was no distraction at all.

On landing for the second flight it took several go arounds again until it looked right. I have yet to find the best throttle setting. I'll work on that again tomorrow. But altogether I'm a happy camper.

RichardGee

My Feedback: (156)

DWR - CONGRATS!!

Was the elevator trim required up or down? - I asked some questions that you answered in your posting - however, your complete post did not appear the first time I looked at it..?[]
Which engine do you have in the nose? R U using DA100, 150 or 3W?

How much full throttle flying did you do and did the R2 appear to be going fast? or did its size disguise the speed?

Did you 3 point or wheel land? How many attempts before you settled in? Wheel landing - just like full scale.

Yours is balanced at exactly 75mm from wing LE- is that correct?

How many flights did you post? Any winds to deal with? 2 flights, no winds. Great job!
Any pictures? Your Gee Bee looks awesome. Additional flight detail would be much appreciated!

Again, CONGRATULATIONS.