25oz RTF mini 3D.
 

Engine is a vintage OS25FP. This is a bushing, crowned piston, 6 bolt head
that should be happy with a 10X3.

I met my target weight goal. Features include:

Carbon fibre sides maintain engine slide pod, my goal is to
have an electric pod to directly replace gas. 3 #2 screw per side
secure pod. Very solid!!!

9" leg custom carbonfibre landing gear. Spectra line retainer

Custom carbonfibre tail skid

4" parkflyer wheels (Needs Dubro HD ones possibly)

KY mouse can muffler

(26) .040 Spectra line hinges

Lightweighted Robart horns , (3) #2 screws no backplates

3mm Titanium engine mount screws.

Custom milled lightweight DB engine mount

4oz custom bubbleless tank (no clunk or brass) moved 2" away
from firewall to minimize C/G shift during flight.

(4) Blue bird servos, metal geared, .58oz weight 50 oz torq

Jr 241 for throttle

270 NMH pack

Berg rx

I have an eclectic airshow fleet of planes from parkflyers, helis to turbine jets.
When I seen this plane fly in Dec after a R/C comabt meet in Cumming GA.
I just had to have one and add my own special hop ups...It should be a blast!!!!

Chris was flying the 35% YAK that day also very impressive but I already have
a Double Vision on order.

RE: 25oz RTF mini 3D.
 

Nice plane, can I buy the gear?

What's spectra Line?

RE: 25oz RTF mini 3D.
 

Nice job c/f! Performance at that weight with that much power will be incredible. Please give us a flight report. That is the lightest Mini 3D I have heard of yet.

RE: 25oz RTF mini 3D.
 

Spectra Line, like fishing line?

Did you weigh the bare airframe before you started? I can't see how your mods saved you 13 ounces (based on 2 pound 2 ounce weight that is common). Did you remove some of the wood or something?

I'd have to guess that the gear and wheels were a huge savings, but what else was a big difference?

At 25 ounces, you could drop another ounce or two by going to a light 15, and still have plenty of power.

The glow or electric conversion "kit" sounds cool. You'll have to post some pics when you get that all done too.

RE: 25oz RTF mini 3D.
 

Based on 2 lbs, 2 ounces as the typical weight, a 25 ounce version is 9 ounces lighter, not 13.

RE: 25oz RTF mini 3D.
 

Chris,

Guess where I got this thing, In Stan Erwins basement, he said it was a club raffle prize.
I even built one of Stans mustangs 4 oz lighter than his and smoked his butt with a 10 year old Webra .32 by atleast 25MPH more...His words not mine.

I had seen the 3D video on the net and was delighted to hit the mother load in his basement as I was picking up a second STANG, first one shredded thru trees @ about 150MPH

The bare frame Mini 3D glued together hinged no gear or hardware was a scant 13 oz on my scale.

Servos are metal gear weighing only .58oz at 50oz of torq and they are glued to .017 carbon fibre plate then glued to sides. There is no metal hardware or grommets.

Spectra line comes from the Kite industry, it provides zero resistance with as many hinges as you desire. Since it's round I insert them into crossmembers effectively dowel pining them for added strength.


Motor mount lightening, titanium screws, there is no steel hardware anywhere. Even the tank has no brass clunk or brass tubing it is all plastic.

KY mousse can available at www.flyingzhobbies.com weighs 1.4oz

No epoxy was used for glueing wing or tail, I cut covering away leaving bare wood exposed and and then spritz wood with water, then using Gorilla glue and ONLY this brand I smeared a fillet of glue on outside only, it migrated in to water and swelled inside and out then I used a dremel tool to shape outside fillet, then painted with paint stick marker.

The .021 carbon on sides was glued using Gorilla Glue (GG) and secured till dry with (3) #2 wood screws down each side. Engine pod comes in and out easily with these screws as securement.

The firewall to the original inside plate has .017 carbon fibre angle stock using GG so there is no epoxy used on this model. GG is an expanding Polyurethane foam type glue that has proven its durability in over 200 rounds of rc combat another passion of mine.

Don't use any other brand glue of this type as the foaming is excessive GG is minimal.

Gear is keyed into fuse carbon fibre sides sitting on top side of original hardwood block and screwed into top of block using 2 #2 servo screws, gear complete barely registers 1 oz. axles are JR #2 servo screws.


I have enjoyed scratch building and flying R/c models since 1974 at the age of 14,
I am anal about trimming the grams, the ounces will take care of themselves.

Check these plastic Robart horns out, no backplates just #2 screws super glued, combat proven!!!!

RE: 25oz RTF mini 3D.
 

Very impressive effort. Yes you are anal :D, but that thing is going to be incredible. Thanks for sharing the ideas and showing what's possible!

Chuck

RE: 25oz RTF mini 3D.
 

Twister,

Engine pods gas or electric is really already done, all I need to do is make a duplicate power pod that has an e-motor speed control and lithium poly battery secured to it. You can see the design is interchangeable within 20 minutes.

Problem is I want 50 oz of thrust for an e verson, and the weight will probably be a draw other than the penalty of fuel. So other than cleanliness the e version has little to offer for a $300 power plant setup.

RE: 25oz RTF mini 3D.
 

Thanx Chuck,

You would'nt know Rick Fraley or Andy P? fellow combater friends of mine.

Another tip you can see in pix is a very small plastic Kraft Hayes clevis and pushrod, these clevises have a metal pin that snaps in so hard you need tools to remove, I have to super glue the robart ball in the horn then sand so that it is same thickness as horn body to get pin to latch. The Kraft Hayes music wire is also exceptionally ridgid as compared to dubro or sullivan IMHO.

Once again I do not want to afford the gram weights of any type of keeper or retaining nuts.

These clevises are also combat proven to the point that HS85MG servos have stripped the remaining plastic gear and clevis still holds many times over.

RE: 25oz RTF mini 3D.
 

I don't have any Gorilla Glue myself (yet), but I've used it a couple of times in a buddy's shop. I was impressed with the stuff. Are you claiming it's lighter than epoxy due to the expanding foam structure? (I'm sure you are). When I think about it, that's gotta be the perfect way to put the wings on this plane since there's a number of gaps anyhow. I ended up epoxying mine and then used thick CA to plug the gaps. I probably have all kinds of weight there. I've watched GG expand and it would have taken care of everything all at once. That's probably a real good tip that everyone can use (well, those that haven't built their planes yet).

Chuck

Edit: No, I don't know either of those two guys. There are four clubs in my local area, and they probably belong to one of the other three that I don't belong to. I'm with the Thompson Prop Busters...but then there's MARCS, Balsa Bashers, and the Burton Club (not sure of their official name).

RE: 25oz RTF mini 3D.
 

Where do you get these Blue Bird servos and who makes them?

Thanks!

RE: 25oz RTF mini 3D.
 

I just did a net search and come up with the following link. These things look very nice. The price on this site was four of them for $80...nice deal (although I've never tried them before...this is a new link for me).

http://www.balsapr.com/catalog/trans...ductId=T886880

Chuck

RE: 25oz RTF mini 3D.
 

Sorry, I forgot to click on "Math Checker" before posting.

What an effort! Anal is OK, as long as it pays off in the long run.

RE: 25oz RTF mini 3D.
 

Balsa products is the only US importer, be alerted......

I have never used them either, no info was available from modelers.

I always open up metal gear servos to add a little slippery grease to preserve teeth and one of my 4 did not want to move smoothly after reassembly. Further analyzing showed me that there is no interlocking feature of the final output gear to the potentiameter shaft. It appears that it is only a friction fit but this may not last, how do they do it with the plastic gear?

I emailed blue bird directly and they are supposed to get me a more technical answer.

They run very smooth and quiet for a metal gear and very fast statically.

So the jury is still out if I loose this model from a servo failure oh well nothing ventured nothing gained. If they do work out they have something that is not available else where.

RE: 25oz RTF mini 3D.
 

Ahhh, so these servos are not yet "combat tested" :D. Please let us know how you feel about them over time, and once you get a response from the manufacturer. Looking over the stats sure make them look sweet if they stand up to use. I can see why you wanted to try them.

Chuck

RE: 25oz RTF mini 3D.
 

Thanx, Chuck

You are correct sorry if I missled you, SERVOS have no history or prior use. sorry to confuse.[:o]

When I get my official blue bird response, I may be adding locktite green to the metal output gear too shaft for a more permanent bond.

If they do hold up they will see combat duty use as they are almost .030 oz lighter, few ounces stronger, few tenths faster AND $10 cheaper, than the HS85MG I currently use.

Since the cases are see thru they appear well made. As for adding lightweight tricks I had replaced the servo leads to a lighter lead and custom length with no coupler weight penalty as with extensions. Weight savings is wire coating not wire gauge. It is also twisted pairs something I like to further improve long lead problem potentials.

As you can see very few items get overlooked as to gram saving measures.

RE: 25oz RTF mini 3D.
 

If anybody is looking for some custome carbon gear You can contact me a [email protected].

RE: 25oz RTF mini 3D.
 

Any word from Blue bird yet?

RE: 25oz RTF mini 3D.
 

c/f:
This one is really nice. As you maybe know my Komacro which is similar in size is about 30oz. without engine!!!!!!!!!!!!!!!!!!!!!! I will think of using some carbin parts to lighten it up. Else I will just sell it.

RE: 25oz RTF mini 3D.
 

Does someone know what prop works best for T/R with a .25LA?

RE: 25oz RTF mini 3D.
 

C/F, whats with the super Extra long wire?

3D-kid330

RE: 25oz RTF mini 3D.
 

3D kid,

The wire is extra long and no end on it yet, once it is installed as a wing servo the wire will be cut to exact length needed to the receiver and then an end plug installed.

RE: 25oz RTF mini 3D.
 

You are a nut!
Now see... i'm with you on the gram counting, I do it myself. Let's see... two rolls of duct tape (540grms), two tubes of JB weld (124 grms), Bailing wire (@ 2 g/foot), and a couple good globs of Liquid Nails (43grm/blob). That's a total weight savings of... Oh wait... hmmm...


Cheers Mate
Bryan

RE: 25oz RTF mini 3D.
 

Hey C/F

Got my gear today , WOW I guess I'm going to need a gramm scale to measure
the weight of these things..........

THANX..............