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Jan 23, 2004, 10:15 AM
Visitor from Reality
Thread OP
Discussion

What's red, white fat and fast?


A Gee Bee swallowed my MaxCim!

The airplane truck - actually, our nice Posty lady in her white UPS van - delivered my Page Aviation Gee Bee R2 yesterday.

it isn't until you get close enough to be about to build one, you realise just how durn big that fuselage really is!

If the plan shows up well, that's the front end of the side view - the two plans sheets are humungously long. That's my MaxCim 13D with 70T spur Superbox - am hoping to get away without going to a Monsterbox on this one. There's a stack of room under the cowl for the ESC too - it'll probably go up in the top of the cowl, as its weight won't increase the top-heaviness by enough to stay awake over, or alongside the motor.

Going to be hard to take any weight out of the kit, though I shall be free spending with lightening holes - have a fresh shipment coming in soon Adrian beat me to it on servos - the prototype flew using HiTec HS85's to start with!

That pack is on the plan is a 10 x CP1700, but it's about the nearest in size to the 14 x 1950 FAUP I plan on using. No problems in fitting stuff in here!

D
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Jan 23, 2004, 10:21 AM
Visitor from Reality
Thread OP
This shows 10 x CP1700 in two sticks of five under the wing and within the outlines of the underwing fairing - brings to mind fitting a tray under the wing and converting the fairing to a magnetically retained battery cover. This would also allow for easy field charging - invert the model, remove the fairing, unplug the pack from the ESC, plug in the charger and let it get on with life.

A snag here is that the MaxCim is replacing an OS91 FS, and this location puts the pack about on the CG - this might not be so much of a good idea.

At this point, we escalate to an "under the hoodbonnet" battery location
Jan 23, 2004, 10:38 AM
Visitor from Reality
Thread OP
Now, not many people know I have these - but that's a pair of seven cell packs on the firewall and clearing pretty much all of the cowl mountings. These are Sub-C sized cells (Gordy Stahl $2.00 specials - still working, if only flown in my Amptique, would you believe?), so FAUPs should be even better if I have to go this way.

By one of life's little quirks, converting her to electric power will make it even easier to mount the fuselage radio. Right now, for glow, the R/E servos are shown as ways up inside the fuselage - be little piggies to reach in there and attend to them. As I don't think I'll be having much in the overwing space, I'll be able to mount them decently closer to the wing aperture.

The rudder drive is incredible - the rudder is so wide at the hingeline, it employs a normal control horn bolted to a plate on the rudder's centreline in plan view - this puts the rudder control completely within the rudder's thickness. I'm looking at ways to put the elevator control inside too, and the ailerons are already driven by seperate servos.

The ailerons are strips in the fine old traditional fashion. Intend to do a little down and dirty research to see if I can't fix her up with more scale-like ailerons, but not sure if this is really all worth the effort.

If I top film-hinge the ailerons very carefully, I could draw the 'scale' ones on with marker pen and a little careful shading ...

Now for a shopping list - Pete's Pilots, for an office manager, some bitsy high power servos and 14 1950 FAUP cells. I have the 4" lightweight wheels. Need some good white film and bright red spray paint. Looking at the under-cowl area, will forego MaxCim's mount for once, and use one of those tube and plate jobbers instead.

Fortunately, the wing and stabs get built first, so I can get going while the shopping arrives.
Jan 23, 2004, 10:44 AM
Visitor from Reality
Thread OP
This is the side view of the above. Despite the shape, I can see that it could even be built nose heavy!

This is the first project I've done where I could be looking at a split battery pack built into the model. As I have this theory that if anything's inaccessible, it will be the first to break, that's unlikely to happen, though it might be close.

I like to have at least an access panel to the charging point and the battery / ESC plug - with the size and complexity of the fuselage, I don't really fancy my usual top hatch (after spending five years developing my top hatch adding skills ???), but the underwing fairing might still have a roll to play here - there's a vast amount of fuselage under wing and I might well be able to make that fairing removeable and have the above access through the wing mount former below the wing.

There's little point in building a Gee Bee R2 and trying to think normally !

D
Jan 23, 2004, 11:09 AM
Extra 330L
Rob Honeycutt's Avatar
Dereck,

I kind of did a double take because this is a new thread with the same title as the one you started earlier in the month!

Anyhow,

Great looking project! Lightweight and lots of power! how many cells could you go up to with that maxcim if you wanted to?

Are the wheel pants and cowl fiberglass or vac molded?

Rob
Jan 23, 2004, 12:12 PM
Visitor from Reality
Thread OP
Hi Rob
Yes, it's the same title. I forgot to go rooting for the old one!

This kit's almost cheating - all the bits that matter are laser cut, but there's a lot of little sticks that need all of one cut each to fit. According to Adrian Page, all the fuselage stringers are "there" for scale too.

I could run the MaxCim on 16, or whip the under-employed 13Y out of my Cub and go to 24 .

The aim is to power it to take off, fly around some acting like the replica Gee Bee R2 in flight - all 'flat' maneuvres, though this model will loop, unlike the full size which would never have gotten to inverted before it stalled - and then land, carefully and with power on.

With 1950FAUP cells, *calc suggests I can get 6 mins of "cruise", which should do me fine. There is enough room in the fuselage to take 3000 nimh if I need longer legs, and the wing loading shouldn't suffer too badly - it's "only" going to be around 25 - 27 oz/sq ft, which is almost trivial by Gee Bee standards - the GP BARF is up around 32oz and all the reviewers say it's a pussycat (surprise!).

I thought about lipo for the legs, as 4S is pretty close in volts to 14 roundies, but then I read the batteries forum to see who caught fire this week and go off the idea of burying something like that inside a model that's going to take me weeks to assemble. Another point against "flatties" is that if I have to, I can scatter 'roundies' around the airframe - some under-cowl, some inside the fuselage - to achieve balance.

Big bonus - Adrian warns against "wheeler" two pointers and recommends a three pointer, lest she end up inverted on roll-out. I figure that wherever the battery ends up, it will all be below the thrustline. As I won't have whatever an OS 91 weighs on the thrustline - it's sidewinder, so still pretty high - I reckon that my electric will be marginally easier to land than a glow version.

He reckons ...

Spats and pants - the kit comes with vac-formed parts, but Adrian does a 'glass cowl, which I'm getting. I've also gotten the vac-formed dummy radial. The wheel pants are very cleverly designed to go on in pieces around the wheels and legs, so shouldn't be too much of a problem. The gear is solid wire, springing is courtesy of 4" Dave Brown Lite tread wheels. I thought about the Robart Gee Bee struts for the bigger GP R2, but it would entail a redesign of the wire struts, so maybe I won't after all.

It's also arrange so that you can take off the front parts of the wheel spats for servicing. Nice touch! The UC mount into the wing is very solid, little chance of collapsing the gear, but this is still one model that's going to demand concentrating on landing.

I've really got to get it to part built, but I've a feeling I can get the elevator pushrod inside the model completely using a brazed control-line style elevator joiner. The kit uses a conventional wire elevator joiner with a pushrod to the right side, so it's pretty inconspicuous, but it would be nice to "lose it" inside all the same.

If I ever trade my posey little Euro-wagon for a real manly vehicle (or even another van!), I'll going to mount this little fat fella on the sideboard and build the 1/4 scale version!

Regards

Dereck
Jan 23, 2004, 12:34 PM
Extra 330L
Rob Honeycutt's Avatar
Are you going to paint it?

It looks like a great project. With it's lightweight design, it should be a lot easier to fly/land than it's reputation..

Lipos would be great, later on, too. A 4S3P pack for it would weigh exactly a pound, and give you 6000 mah of 'leg room'


Rob
Jan 23, 2004, 12:35 PM
Ron
Ron
Registered User
Dereck...... looks like a great project....I am thinking to build the
GB Z model next winter..............( I like the black and yellow colour scheme) .......... Have been using the Maxcim on several models from F3D on 10 cells to 68" D V111 on 14 cells, to 1/4 scale Shoestring on 20 cells. . I'm using a 3.69 to 1 reduction, and this setup just works well. On 10 cells it is swinging a 15 1/2 X 10 prop at 38 amps.. I'll be interested to see how your model works out as I will be able to put the information to good use.
Jan 23, 2004, 12:49 PM
Extra 330L
Rob Honeycutt's Avatar
Ron,

you may have already seen it on tower hobbies, but in case you haven't , the kyosho gee bee yellow/black is on sale .. I think it is 60 or 70 bucks off.

Rob
Jan 23, 2004, 01:25 PM
Ascended Master
Sparky Paul's Avatar
"magnetically retained battery cover".. hopefully -covers- the batteries, which are secured to the airframe...
Jan 23, 2004, 01:55 PM
Use the 4S Luke
feathermerchant's Avatar
Just got my Page Gee Bee too! Construction looks pretty straightforward but finishing looks intimidating. Adrian said he used a Satio 90 FS on his prototype (AUW 6.25 lb) I think the Satio weighs about 20oz or less and ha said he had to add an oz of lead to the nose for balance. I'm thinking of using my Mega 22/20/3 and superbox at around 5 or 6 to one. 4S2P Tanic 2600's look good. Thought about mounting 2S2P on each side of the motor mount. Like the idea of hiding the elevator control. Will look at pull pull for ele and rud. Lighter and should help the CG. Will use flaparon mixing to help with slow speed flight.
You should see the full scale replica fly. Was at an airshow here a few years ago. Does all kinds of aerobatics.
Jan 23, 2004, 02:33 PM
Visitor from Reality
Thread OP
Paul - battery hatches should be non-stressed and real light - they are there to organise the airflow, not hold up batteries You won't find any holding up batteries in my fleet - I get nervous if I can't mount the tray under the pack!

I wouldn't confuse the BARF Z with Adrian's kits. For one thing, there's this tiny weight issue ...

Never got to see the full size R2 fly, but I did see Keith Shaw's 16 cell R2 fly at the 96 KRC. Despite what he said about all bets off when the wheels touch, it looked to land as good as it flew - which was pretty spectacular. Keith's was re-engineered from a 40 sized glow plan that usually was 'improved' to weigh around 6 - 7lb and need a 60! Keith's actually weighed a little under the quoted 40 powered bracket! He's since remotored it with an Astro 05 BL and ten cells, which has improved it considerably so I understand. I think Keith's might be a little smaller than Adrian's design - 54" span comes to mind, but I aren't that sure.

Ron - according to "*Calc", a 13D on 5:1 and 14 cells can swing a 15 x 10 at 5,900 burning 39A. Pitch speed is 56MPH, stall speed around 20 MPH. Should be enough to get some air around the cowl (12" dia near as makes no odds) and cause her to commit aviation.

Funnily enough, I have a Z kit as well. However, it isn't one that Adrian made, though its off his design, and might be somewhat more "interesting" to assemble than Adrian's. It's a small, skinny looking thing alongside the R2 ... Might be fun to build that one day.

I always fancied that wild canard that Gee Bee built to see 'what if' too ...

D
Jan 23, 2004, 09:03 PM
Ron
Ron
Registered User
I tried computer programs to see what they said, and if I went by what M calc predicted for my max...I'd never have given this a try...typically it is out by 35 to 45% on the amp draw.
This seems to have been a continuing problem with brushless setups. Now, I try it with an ammeter and a thrust measuring scale. This is a little more work than the "calc" programs, but it produces real actual results that you can " take to the bank" :-)
Jan 23, 2004, 09:36 PM
Senior Soil Sampler
tim61's Avatar
Dereck,
That kit looks awesome. I am following your build closely. This is VERY tempting.
Don't be fooled by all the Lipoly fires you hear about. Lipoly's are very safe as long as you don't do anything stupid with them. Don't charge or discharge beyond the recommended rate, and you will be fine. Lipoy's don't start fires, misuse starts fires
Tim
Jan 23, 2004, 10:06 PM
Visitor from Reality
Thread OP
Hi Tim
Two things stop me going lipo - one, the technology hasn't matured to where I'm happy with it yet. Two, maybe three years (or soon after Bob Villa starts shilling hefty lipo - fueled electric power tools for Sears ), I reckon I'll have joined in.

With state of the art batteries, well sorted out chargers and about as much chance of burning the house down as with nicads.

Two - I have two real expensive hobbies and have just bought myself a custom bike Okay, it's not a CF Trek like that Texan peddles around France in July, but it wasn't cheap - end of big ticket hobby budget for a while

If you must know, it's only my fifth new bike since I started back up in cycling four years ago, but I don't take it too seriously now.

Yet ...

Tim - you need something like this. Go on, admit it Not too much like this - we don't want them to become common though. Next thing, everyone will have one and where's the mystery? Can you imagine RC if everyone bought similar models, each one done in the same colour scheme as thousands of other?

Sorry - what's that?

Regards

Dereck


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