Toronto Electric Model Aviation Club Forum

Toronto Electric Model Aviation Club (TEMAC) => Building / Construction => Topic started by: msatin on March 06, 2023, 08:55:57 AM

Title: Build - BMJR Fiasco
Post by: msatin on March 06, 2023, 08:55:57 AM
I found this kit on BMJR Models and seemed like a good 3rd build.
It won't be as interesting as some of the other projects from more experienced builders (see Michael, Frank Rob, Guy, David's 3D, etc  ;)), but for anyone interested in starting to build, it demonstrates that no matter how badly you screw up, there is always a fix  ;D
It has a 44" wingspan; 2826 1100KV motor, 30a esc; 10x5 prop.
Started off pretty straightforward

Title: Re: Build - BMJR Fiasco
Post by: msatin on March 06, 2023, 08:57:21 AM
A few more
Title: Re: Build - BMJR Fiasco
Post by: msatin on March 06, 2023, 09:00:19 AM
Motor box was actually 2 pieces. The 2nd on the right allowed for placement of the motor so that the prop cleared the cowl.
The cowl was built up using a jig.
Title: Re: Build - BMJR Fiasco
Post by: msatin on March 06, 2023, 09:09:49 AM
Now some covering.
I used Ultracote, which turned out to be a good choice.
It was fairly easy to work with, but the real advantage was how much it shrank when hot air was applied. See 5143
I also learned (unfortunately later on in the process)  that by tacking the covering, and then very carefully applying hot air before ironing the entire section, I was able to avoid a fair bit of creasing.
The wing and h-stab tips were essentially thick pieces of balsa that needed to be sanded into shape. The difficulty was making sure that both sides were as identical as possible.
These were also very very rounded which made covering them quite challenging.
Title: Re: Build - BMJR Fiasco
Post by: msatin on March 06, 2023, 09:10:25 AM
wing tip
Title: Re: Build - BMJR Fiasco
Post by: msatin on March 06, 2023, 09:12:06 AM
Fuselage and wing covered
Title: Re: Build - BMJR Fiasco
Post by: Michael on March 06, 2023, 09:14:03 AM
Nice build!
Title: Re: Build - BMJR Fiasco
Post by: msatin on March 06, 2023, 09:20:10 AM
1st major mistake.
The h-stab did not fit snugly into the opening, so I had to put in a bunch of shim material to make it a solid a fit.
However, I was so focused on this, that I wasn't paying attention to ensuring the stab was, well... actually Horizontal.  :o
Because the fuse and stab were already covered, I didn't want to do any more damage cutting out the shims so it took quite a while.
Title: Re: Build - BMJR Fiasco
Post by: msatin on March 06, 2023, 09:27:18 AM
A couple of other interesting things for me
I finally learned how to insert CA hinges. I have had a lot of trouble with this, as the hinge always would get crumpled or the fabric would come off as I tried to insert it into the slot
The trick (at least it worked for me) was to make the slot quite a bit wider than the actual hinge.
After getting everything installed, I went to place the wing into the crutch only to discover that the linkage stopper was in the way. So I removed the linkage stopper and put a Z-bend (much easier than I thought) in the push rod.
Title: Re: Build - BMJR Fiasco
Post by: msatin on March 06, 2023, 09:31:17 AM
Final pic - Ready to fly.
Thanks to Frank, who, while recovering from surgery, was still able to provide good guidance and tips.
Title: Re: Build - BMJR Fiasco
Post by: msatin on March 06, 2023, 09:36:12 AM
Thanks Michael
Title: Re: Build - BMJR Fiasco
Post by: davidk on March 06, 2023, 10:20:26 AM
She's beautiful... and in Rogo's official colours!

What's the motor, prop, ESC?

Nicely done Mark.
Title: Re: Build - BMJR Fiasco
Post by: msatin on March 06, 2023, 11:13:49 AM
Thanks David.
It's a Propdrive from HobbyKing. 2826 1100KV motor, 30a esc, also from HobbyKing; 10x5 prop.
I have the designated garbage bag ready for the maiden. LOL
If it flies nicely, I will try printing decals (special paper for this) on my printer
Title: Re: Build - BMJR Fiasco
Post by: Frank v B on March 06, 2023, 01:29:41 PM
Mark,

When you started you said the model was aptly named.
From Wikipedia:

"Fiasco: a failure or humiliating situation"

Where's the failure??
Looks great.

It is hard to describe to people how satisfying a successful maiden is on a plane you built yourself.

To other TEMAC members: go build something that flies!  You'll love it.

Frank
Title: Re: Build - BMJR Fiasco
Post by: Georgetsigaridis on March 08, 2023, 09:35:58 AM
Hi Mark
Enjoyed following your build. Thanks for the tips along away. They are invaluable to newbies like me in the build process.

Thanks again and keep building.
Title: Re: Build - BMJR Fiasco
Post by: Frank v B on March 08, 2023, 10:34:03 AM
Mark,

Looks great to me as a charter member of the 50/50 club*

re: your "I have had a lot of trouble with this, as the hinge always would get crumpled or the fabric would come off as I tried to insert it into the slot"

2 tricks I use:

1) after you cut the balsa with the sharp end of a pointy #11 blade, turn the blade around and do a few passes with the unsharpened end.  It scrapes the joint open to turn a slit into a slot.
2) cut off the 4 pointy corners on each CA hinge so it does not snag as you push it into the slot.  It funnels the hinge into the slot.  See thumbnail photos from my Guillow's B25 build post about cutting the corners off CA hangs. If you wish to enlarge https://temac.ca/smf/index.php?topic=7745.60

This usually works.

Frank

* 50/50 rule- if you can't see the mistake at 50 feet and 50 km/h don't waste your time fixing it.   ;)
Title: Re: Build - BMJR Fiasco
Post by: Gregor77 on March 08, 2023, 06:49:14 PM
Mark, you may want to up the pitch on the prop, my experience is that a 5 pitch is going to do nothing to move the plane.  Even a 6 pitch is not enough, 7-10 pitch are good, but do a watt test to make sure it doesn't draw too many amps.

Example:  6 pitch was used for nitro planes as far as I can tell, mainly so idling they don't start flying away.   The LT40 I have has a 6 pitch 12" prop and its terrible, I am at 3/4 to full and its barely moving, plus the battery lasts a good 20 mins.  I would rather have some extra horse power and pull and less play time.

As far as electric, you just need to fly nice at 1/2 throttle and the rest if you want to be sporty with it.   

My 2 cents!

Awesome build by the way!

Title: Re: Build - BMJR Fiasco
Post by: msatin on March 08, 2023, 10:09:10 PM
Thanks George.
The most important piece of advice I can give to anyone interested in building, is to not hesitate to ask for help.
This club has an abundance of talented people who are always available to provide guidance.
Title: Re: Build - BMJR Fiasco
Post by: msatin on March 08, 2023, 10:23:05 PM
Interesting observation Greg - Thanks!
I've never measured the amp draw on any of my planes. I guess it's time to start.  :D
I think I will bring several props, based your pitch recommendations, to the maiden, and select the best matched
Title: Re: Build - BMJR Fiasco
Post by: Michael on March 09, 2023, 07:31:44 PM
The specifications for the motor you are using recommend a propeller with 9" diameter / 4.5" pitch.

If you use a prop with 10" pitch, I guarantee you that something will burn.

Your original choice of using a 10/5 propeller is a reasonable start.
Title: Re: Build - BMJR Fiasco
Post by: msatin on March 09, 2023, 11:38:17 PM
Thanks Michael.
I think that's the correct path.
Start with original choice, and have a couple of other options to test if necessary