RE: Dirty Birdy Build Thread
 

Of course, it is also possible that Uncle Willie is paying royalties for the commercial use of the Bridi plans. Who knows? I don't think I'd call him a crook without knowing the truth.


Ed Cregger

RE: Dirty Birdy Build Thread
 

That's refreshing Ed. Innocent until proven guilty. What a concept. :D

I'm back on track with the Dirty Birdy. I needed to get a fuel tank and some other hardware before I felt comfortable moving on.

I did add a filler block to the top of the nose where the engine would normally protrude.

I bought the Sullivan 16oz flex tank since it was one of the few that were less than 16" long to fit between the firewall and bulkhead #2 and leave room for some foam rubber.

I can't wait to start making some sawdust.

RE: Dirty Birdy Build Thread
 

One nice feature about the kits of the day was that they always included a full size plan to go along with the kits. I may still have mine somewhere in the box of plans.

I built the Tweety Bird, Dirty Burd 40 and 60 size Bird back in the day (around 78 and 79). They all flew the schedules of the day well.
The 40 and 60 models were trike retract equipped. The 40 size was heavy with retracts and flew heavy as I recall.

I had just started to play around with piped set-ups when I made a paradigm shift into Arrows with the pipe running down the fuse top. The Arrow was and may still be the truly outstanding rolling model of back then and now. The MK Arrow kits were amazing

MattK

RE: Dirty Birdy Build Thread
 

A little more progress made on the fuse. The motor is mounted and the nose is roughed in.

Next I'll install the throttle and mixture pushrods. I'm going to install a plywood plate behind the head for the fuel dot and tank pressure line instead of running the lines through the firewall.

Once that's done I can install the tank floor.

RE: Dirty Birdy Build Thread
 

A couple more photos. There's one shot with the Dirty Birdy fuse next to my 35% Panzl. Looks small.....

RE: Dirty Birdy Build Thread
 

The pushrod tubes for the throttle and in-flight mixure are in. The tank is plumbed and the plywood inlay is in for the fuel dots. The tank floor will be glued on tonight then it's on to the tail feathers.

RE: Dirty Birdy Build Thread
 

I started on the Stabs.
I first layed out the locations for the hinges on the trailing edge. I'm using Robart hinges, so I then drilled a 1/8" hole at each location. Since the trailing edge is very thin, I added hard balsa blocks for extra meat for the hinges.

RE: Dirty Birdy Build Thread
 

Hello Jeff ( allthegoodnamesaretaken),

I'm also building a DB .60 I purchased from GS Hobbies ( Joe Bridi ) about 5 years ago. I'm going back to kit building, I lost a Yak 54 by Aerworks, i didn't hook up the ailerons leads. My stupidity.
I have been looking at your articles on the DB and I like the way you are going about it. I like the photos. I'm in the process of glueing the fuel tank upper block and the bulkheads to the upper fuse slab. I'm sticking to the plans with the exception of using Robart retracs. I woul like to paint it but fuel proof paint is hard to come by. I will use film.
I have 3 Rossi .60 engines, one side & 2 rear. I'll be using the side exhuast with a Nelson hipo muffler.
In looking at the pics ,you furnished, there are some that are missing. I can't find them any more. The ones I can't find is the one where the fuel tank slab and the fuse top slab are shown, It is a frontal shot. The glue that you are using (TiteBond II blue ), doesnt this glue warp balsa? So far i have been using epoxy for glueing the fuselage sides & joiners.
I would like to take pics as I go along.
My next project is a Career .60, a copy of the Curare by Mutchlers Hobbies. It has a glass fuse. After that I will build a Double Eagle .60 from scratch.
I'm staying away from ARFS IMAC type birds.

Ben Cubillos

RE: Dirty Birdy Build Thread
 

Ben,

You mention that fuel proof paint is hard to come by but it's not. "Hobby" epoxy based paint is available which is fuel proof and they match Monokote colors if applied properly (i.e., you use the right primer). An alternative would be to go to your local hardware store and you could choose from the various epoxy based paint they carry. Ultimately, you could use non epoxy based paint which is compatible with fuel proof clear which you would likely spray as a final coat.

http://www.monokote.com/lustrekote/lustrekote.html

http://www.klasskote.ca/

I'm in the process of deciding whether to cover or paint a fuse I'm finishing but am leaning toward the latter - only problem here is painting in winter temperatures. Shouldn't be an issue in El Paso! :D

RE: Dirty Birdy Build Thread
 

Hello doxilia,

Thanks for the paint information. I will print a copy of the paint info so I can order some. All pattern people are very helpfull.
I will furnish pictures of my bird as I build along.

Fly Low ...
Fly fast ...
Turn Left ...

Ben Cubillos

RE: Dirty Birdy Build Thread
 

Ben,

cheers. There's nothing quite like the look of a painted pattern aircraft... or F1 if I understand your signature. The DB, would probably look nice with a painted fuse (glassed before hand, of course) and film wings. I think the DB has open structure wings (not fully sheeted) so paint on the wings would be more laborious.

Looking forward to seeing your build progress!

RE: Dirty Birdy Build Thread
 

I have used KlassKote (and am currently finishing my latest design with same). It's very good material and I highly recommend it, even in cold climes (Our Canadian friend who wrote about it above).

I use the epoxy paint for bedding the glass (or in my case, carbon matting). I "glass" the whole model this way, wings and tail included. Lots of care used of course to avoid too much weight build up. For example, my stab/elevator in my new design is approx 240 sq in and weighs in at 4.5 ozs painted.

One wing panel of my new design is approx 540 square in and weighs in at 12 ozs fully balsa sheeted, glassed and painted and ready for the servo and linkage. Under 14 ozs rtf. It can be done, you just have to be careful. It will fly with a gas engine so it is strong enough. Carbon matting under the balsa sheeting next to the foam and oven the sheet as bedding for the paint.

BTW, carbon matting stiffens the structure nicely. No more flimsy ailerons elevators or rudder and very light too

MattK

RE: Dirty Birdy Build Thread
 

Hello Ben.

Titebond can warp wood if you use a lot of glue and don't clamp/weight/pin the structure. One thing to keep in mind when using that type of glue is that it's water based, and the water can/will expand the wood and cause warps when doing sheeting etc. But if you clamp/weight/pin then once the water evaporates and the glue dries, the structure will not be affected.
I rarely use CA anymore. I find the Titebond gives me lots of time to make sure everything is lined up and where I want it. It's slower, but I find I'm more accurate with alignment and parts fit.

BTW, I plan on glassing the fuse and tail with 3/4oz cloth and painting with Klasskote. The wings will be Monokote.

Regards

RE: Dirty Birdy Build Thread
 

Jeff,

I received my Dirty Birdy kit yesterday. Can't wait to get started! So I'm studying plans and instructions and trying to follow your thread with both in hand. It seems you did not cut an opening in Bulkhead #2 to get to the tank? Not worried about having to get to it later?

Also, in preparing my shopping list, what tank did use?

Can wait for more pictures from you plane!

-Peter

RE: Dirty Birdy Build Thread
 

Hello Peter,
The kit that I have is from G&S Hobbies and it is a five year old kit. The instructions are vague, out of sequense and at times do not make sense. If you have built fron scratch or kits I'm sure that you can get by. I've looked at other methods of building this bird and it doesn't looked like anyone is following the instruction booklet, that includes me. I have drilled the firewall for Sig composite mounts, upright engine mount, Rossi, 5 port engine and Nelson HP muffler. I'm using a MK 12 oz. fuel tank. I have drilled and installed blind nuts for Robart #607 firewall mount retract. It is slimer than the metal SpringAir type retract. I also drilled a hole for the fuel tank stopper. I feel that it is easier than drilling holes for the fuel lines. So far that is where I'm at. I had to stop because I also have to finish an FA/18 twin ducted fan, Electric, from HET.
I will finish the Jet in two weeks and I will continue the DB. I will be using foam core wing and stab from Eureka.

Ben

RE: Dirty Birdy Build Thread
 

Dirty Birdie .40,
Does anyone have a kit or built Drty Birdie .40 for sale? I'll answear all responses. I haven't see any advertisements for this bird. I have a nice YS .45 that I like to use in it. I had a Kaos .40 from Tower Hobbies but it left a lot to be desired. It would not track strait on stall turns and knife edge was brutal. I'm also building a DB .60.

Ben Cubillos

RE: Dirty Birdy Build Thread
 

Hi MattK,

do you have some pictures and/or a brief description on how you go about the carbon matting above and below the wing sheeting?

Is the matting below the sheeting applied with laminating epoxy or epoxy based paint? What type of matting do you use and where do you obtain it from? Does it have a tendency to curl or does it lie flat like fiberglass? Does it tend to shred a bit like 3/4 oz glass cloth?

For the top layer, do you apply epoxy clear paint (mat or gloss - does it make a difference?) first and then lay the matting on top? What tool do you use to insure a tight junction on the sheeting without lifting up the matting?

The end result must look pretty cool. Is it much lighter than glassing? (I know it will be rock solid).

Hope you don't mind the 20 questions.

Thanks, David.

RE: Dirty Birdy Build Thread
 

indeed, please enlighten us as to your techniques.

thx, david

RE: Dirty Birdy Build Thread
 

David, I started a thread on Composites Fabrication and Repair section which I called Finishing with Carbon Veil. I have photos there that should help.

Inside the skin is straight forward also: carbon is first layed down with nitrate and the paint is allowed to fully flash a couple days. This does at least two things: it builds practically no weight as it adheres the carbon veil and seals the wood making it ready for epoxy or other (PolyU). I use Pro Set epoxy, 125 resin 229 hardener (various sources; Look under Gougeon Bros) for a very thin viscosity of around 380 cps. It's as thin as canola oil. Working time is over 1 hour so there's plenty of time to get everything aligned. Nitrate is extremely thin onced diluted with solvent and adds no real weight...maybe a couple grams per sheet.

I get carbon veil from ACP, but FibreGlast, CST and AS&S carry it also. I use and recommend the 0.2oz variety; it's very thin and it takes almost no glue to lay it down. On the other hand there is also the 0.5 oz type but don't let the light weight fool you. This material is fluffy and tends to hold much more glue. It definitely has its uses particularly if you vacuum bagged an assembly where the laminate could be squeezed down

After the carbon layup has flashed, I roll the epoxy sparringly thru the carbon and onto the wood. I also "activate" the foam by running the wet roller onto the foam briefly. This removes any vestige of polystyrene particulates providing a better base for the epoxy to adhere to.

The assembled wood and foam is then placed in a bag and vacuum is applied; around 6" Hg is what it takes. I place the vacuum assembly onto a husk and leave it alone overnight with vacuum on the whole time. Strength is foam tearing which as good as you can get.

Learning vacuum technique is highly recommended; I use it for everything I laminate. I may show you guys soon (especially if there is interest) how to carve wood props and finish in vacuum laminated carbon cloth. You can get pretty much any shape prop you want to experiment with by taking existing products and reshaping them, producing a thinner more efficient shape with better area and pitch distribution. You would be amazed how inefficient available wood propellers really are especially for the larger gas engines.

Another lamination type that uses vacuum is fixed landing gear struts. Carbon layup over balsa wood is what I often do when I am in a pinch and don't have a mold ready. Must be vacuum laminated for best results for strength and lightness. My landing gear for a typical 140 sized pattern model at 11 lbs, weighs in at a scant 3.5 ozs which includes pants axles and wheels. Compare that weight with anything commercially available. The gear on my primary pattern model is entering its 6th season next year which speaks volumes for the mechanical strength of the gear set-up I use.

MattK

RE: Dirty Birdy Build Thread
 

i've seen that thread but didn't think to check to see if it was the same author. i am listening/learning for sure.

thx, david

RE: Dirty Birdy Build Thread
 

Matt,

nice thread. What about sourcing the CF. Any recommendations?

David.

RE: Dirty Birdy Build Thread
 

<xml>This winter I bought a DB-60 kit from BlueJay, and finally did the maidenflight yesterday. It flies supper nice. I consider myself still a beginner and I was able to land this airplane with a very nice long roll.I'm very happy about it.

Completing the kit was a little bit of a challenge for me, since the wood, the plans and the instructions did not always make sense in the first read. I had to take my time, think it over and re-read the instructions, and in a few instances go my own way.

Some tips (which might be obvious to some, but were not to me):
- Measuring my OS-60 engine and the plans, I decided to move the firewall back about 1/4 inch to allow for the prop to end up in the same place, and not needing longer fuselage sides.
- I used a different nose gear than what was delivered in the kit: I used a taller one to keep the 11x7 prop off the grass, and also used 3" wheels for main gear. Looks a little big, but gives nice clearance.
</xml>- Ikept the control horn on the steerable nose gear inside the fusefale, but to get that working had to hollow out the bottom nose block and the side support block. You have to play wiith this before you final glue these pieces or else it's very hard to get to.
<xml>- Even with the battery pack tight against bulkhead #3, I still needed a lot of dead weight in the tail. I found this out after covering. If I had balanced it before, I would have created a battery compartment further back in the fuselage. If you need weight, it might as well be the battery.
- The plans and instructions did not mention throws. Lynn from BlueJay suggested 5/16" for ailerons, 3/8" for elevator and 1 3/4" rudder. Somewhere else I found 3/8" for ailerons, 5/8" for elevator, 1" for rudder. So I set my dual rates around these values. With my limited skills I was able to keep it under control on high throws. Once I get more familiar with it, I might turn it up a notch.
- To give the canope something to hold on to, Iglued pieces if 1/8"x1/8" balsa on top of the fuselage.

</xml><p class="MsoNormal">I will try to attach a picture. Some might recognize the color scheme: it's taken from Scott Sapington's Daddy Rabbit on the front of AMA magazine March 2006.</p>

RE: Dirty Birdy Build Thread
 

Hey Peter,

That's onebeautiful DB you have there. If that's theplane you built from the kit to mentioned in your post back in October,you sure build fast....http://www.rcuniverse.com/forum/js/f...sn/biggrin.gif Please keep us posted with the maiden. I'm sure it will fly as good as it looks.
</p>

RE: Dirty Birdy Build Thread
 

Hello RCU friends.

I started this build over a year ago, went gangbusters on it for a month or so, then put it aside to build a 35% Panzl (in my avatar). There were a ton of issues with finishing my Panzl - mostly Monokote problems - no need to discuss. But anyhow, I was severly discouraged by all the problems I had over most of last winter with the Panzl, that I put all my R/C stuff aside and bought a boat.

Well, summer is over and the Dirty Birdy looked so helpless in its half assembled form that I've decided to resurect the build. I had some pictures of the stab assembly, but the camera that held those photo's is broken.

So here is the status of the build as of today:
The fuse is 75% constructed with the engine mounted (temporarily), the plumbing installed and the nose roughly shaped.
The stab is 90% completed and just needs final sanding.
I have started on the wings and have spent the last couple nights working on the retract mounts for the main gear. - Remember that I'm going with a tail dragger and the spar placement is making the retract and wheel well placement tricky.

***Does anyone have photo's of a DB as a tail dragger? I haven't finalized a tail wheel set up.

I promise to post photos in the next day or so for those that are interested.

RE: Dirty Birdy Build Thread
 

I built a DB a couple of years ago that was set up as a tail dragger, although it flew great, it was a bear to keep from nosing over on take offs and landings. I went through a lot of props and had to patch the nose quite often.

I would recommend going with trike retracts. Or fixed gear well ahead of the leading edge. Mine had the gear about 1.5" in front of the leading edge with the gear extended. It’s doable, but I would be money that you will get frustrated and move on to other birds, I know I did. However I am planning to build a new one this winter with trike retracts. Of the three I have had (2 trike one TD) the trike geared models were much more enjoyable on the ground. I still have the TD DB it makes great decoration hanging in the basement. LOL. I decided to go with the TD to save a little weight, but trust me it’s not worth the frustration!!!! Just my 2 cents. I wish you better luck than I had if you decide to proceed with the TD set up.