Megabar Plug is cut
 

Thanks for all the great comments..

I have been thinking about the finish for a while
and I really don't know... Maybe someone could
help me out here.. I was just thinking of painting
it with thinned exoxy and then see what I get..
I don't plan on putting glass on it. All this mold
stuff is new to me..

Eddie

Mega Bar
 

When I saw the title to this thread and then saw the author's name I thought that we were in for a new addition to the Eddie Weeks custom trailer----A MEGA BAR where those Louisiana rum drinks flowed freely and all the mud bugs you could eat. I must say....I'm deeply saddened. :cry: :D

Eddie---Good luck with your new project. It's looking great!!!

Kevin

PS---I got the outer case off of the Merc with no problems after your help---Thanks!!

Megabar Plug is cut
 

A friend of mine has built an NC router with MDF as the frame material. He finished it with some sort of clear coat and said that it was incredibly thirsty stuff - it just kept sucking it up. He will try some parts that I have lofted and I personally would go for epoxy resin and hit it with a heat gun. That makes it get really thin so it can soak it, without watering it down which sometimes affects the properties of the resin. I would do that until it stops soaking in, then it it with a good primer - either an automotive 2 part or one of the polyester ones like Featherfill or Duretec which take a catalyst and cure rock hard so as not to be affected much by heat.

Please keep us posted on how it works out.

Megabar Plug is cut
 

Eddie,

If you can rustle it up, it might be worth trying the UltraPoxy Primer. This is the new stuff from K&B.

I have used it and it seems to have a high solids content and cures rock hard. Hard work to sand if you let it sit for more than a week though.

Regards,
Garrett

getting ready to cut formers
 

Eddie Weeks

Megabar Plug is cut
 

Eddy, go to your auto paint store and get some Evercoat Polyester Feather fil Primer. sands like butter. I use it and a comercial product that is the same except you have to thin it. The featherfill is already thinned and all you add is the cataylist. (Mek)

Megabar Plug is cut
 

I starting stuffing the Megabar with parts. I am using
the Isobar Wing plug in system. It took a long time
to get to this point but its starting to pay off.
I design two 67 oz fuel tanks that I know will fit.
(the one in the pic is ~40 oz)

Using Solidworks I was able to make a very smooth
intake, and a bypass that will hold an AMT450.

Eddie Weeks

Megabar Plug is cut
 

I spend all day at the machine shop cutting
the plug for the back hatches today. Here is
a small video of the final cut of the right side
back hatch.

RPM 5100, Depth of cut 0.062
Feed Rate 200 inch/min
Cutter: 2 inch Fly cutter with 4 carbide inserts


www.corpcomp.com/weeks1/movies/Back_Hatches.WMV

Eddie Weeks

Megabar Plug is cut
 

Roughing out the hatches...

0.400 depth of cut...

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Finish cut

Solidworks
 

Hi Eddie

Great project. A few of questions

1.) I assume you are doing all of this on a 3 axis mill. Is this mill special made to do this type of work (ie lighter duty cause all you are cutting is foam or wax or wood...etc.)

2.) Did you think about directly cutting the female molds? I can see how with a 3 axis that might be hard.

3.) Solid works. I assume you used the lofting command a lot. How did you decide where to put the guide points for the loft on each cross section? I keep looking for software that will do this like magic, but it looked to me like with Solid works you have to do it manually.

4.) How did you design that bypass? If you ever want to offset some costs I will buy one from you. What is the inlet diameter?

You really need a P-200 for that :-)


Anyway very impressive work.

Re: Solidworks
 

1.) I assume you are doing all of this on a 3 axis mill. Is this mill special made to do this type of work (ie lighter duty cause all you are cutting is foam or wax or wood...etc.)

No.. the mill is a standard metal cutting mill... When it was
new, it went for ~$100,000... You can get the same mill
now for ~$50,000

2.) Did you think about directly cutting the female molds? I can see how with a 3 axis that might be hard.

yea.. we were going to cut the mold itself, then I got
a price for an aluminum 90"x13"x7' and bout fell out...
and they would be too big and heavy to vacuum bag.
I was told that building a few molds was not that big
a deal...

3.) Solid works. I assume you used the lofting command a lot. How did you decide where to put the guide points for the loft on each cross section? I keep looking for software that will do this like magic, but it looked to me like with Solid works you have to do it manually.

Your right.. Each cross section has 8 points... no more. no less
The #1 point on cross section A must line up with #1 point
on cross section B... There are no guide curves.

4.) How did you design that bypass? If you ever want to offset some costs I will buy one from you. What is the inlet diameter?

I just plan on making a few planes, but with the very
low part count, I may make a builders kit. (builder does
a lot of work)

I drew a AT450 (the biggest turbine that it will fly with)
and then drew a nice smooth curve around it. That's it.
I made sure to leave 0.750" gap.. No big deal..
All other turbines will just have more room.
It will most likely fly with AT400s or P160-P200
if we can get them.

I should be flying the first plane in 4-6 months, I will keep
this thread updated, but you are the first on the list to get one...

Thanks again
Eddie Weeks

Slow down son!
 

I just want one of the giant bypasses not the plane! I don't have room for another kit!!

Megabar Plug is cut
 

I just put this together

~10 meg

its a 55 sec movie of CNC cutting MDF (wood)

http://www.corpcomp.com/weeks1/movie...ck_Hatches.WMV

Eddie Weeks

Megabar Plug is cut
 

Here are two intakes that I designed for the Megabar..

Witch one do you think would work better. ?

One, with more less constant area or one with lots
of area.

Eddie Weeks

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or this one

Air Intakes
 

Hi Eddie,
Nice project. As far as intake ducts go for our models the more volume you have in front of the engine the better. General rule is that any duct that expands in volume should not have a sidewall slope of more than 7 degrees to prevent seperation of the airflow. This means that the air in front of the turbine is moving slower than at the intake and thus has more pressure, helping the compressor a bit and countering the negative pressure effect of the exhaust venturi effect in our bypass sytems from reducing the pressure the inlet sees. Narrow inlet duct + lots of bypass = easy flameout of the engine.
Cheers,
Andre

Megabar Plug is cut
 

We started cutting the nose sections at 7:00 pm
and finished about 4 hours later.


Here is the computers ver of the nose.

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I did not get any pics of it cutting but when I
took a few when I got home.

It looks just like the drawing except it's BIG.
This plane is bigger than I thought it would be.

Megabar Plug is cut
 

btw.. the hatch fits perfect.... non of these pices
have even been sanded yet.

Eddie Weeks

Megabar Plug is cut
 

You need to start on a pocket sized model - the millibar! :p

Hi Eddie
 

What is the diameter of the inlet throat on your bypass?

You mentioned a .75 clearance around the turbine, is that correct?


TIA

Megabar Plug is cut
 

I just wrote this long post about bypasses and how
to design them....

I attached a pic that was too large, I hit the back
button and RCUniverse lost my post... :confused:

Eddie Weeks

Megabar Plug is cut
 

Eddie,

That engine looks like a JetCat, what with that nice looking purple inlet cover!!! Glad to see you finally saw the light.

DR

PURPLE INLET
 

David,


Wrong again Buzzard Breath!!! :eek: As Eddie calls it, that is a Purple Faced Pegusus.. Just like the one I got.. AMT Netherlands Pegusus HP... :D Tell everybody Merry Christmas over there.. see ya'll at Florida Jets!!!

Danno :cool: