Martin 167 Maryland design and build. - Page 8 - RC Groups
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Feb 25, 2009, 03:09 AM
What could possibly go wrong?
nickchud's Avatar
Originally Posted by RyanPSU21
I'm really making this part up as I go now and still not really sure how all the costruction will go.
Man after my own heart.

Looking good, Ryan.

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Feb 25, 2009, 09:25 PM
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RyanPSU21's Avatar

This plane is kind of a test bed for ideas for my next plane which will be a larger design with 4 motors again. I've only designed one small sport plane myself before so this in itself is a fairly large challenge right now.

I got made a top and bottom nacelled former tonight and then got those attached and the firewalls attached on to them. So I just need to fill in the meat of the structure now.
Feb 25, 2009, 10:46 PM
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D-Rock's Avatar
Ryan, really nice! I like your idea on keeping the firewalls parellel to each other.

Mar 01, 2009, 11:47 AM
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RyanPSU21's Avatar
I got the nacelles done to the point they are ready to be planked now. Well almost anyways. The motor mount blind nuts need to go in and the front plywood part needs to get swiss cheesed a bit. Wires for the motors need to be run also. I think I am going to take a break from the wing and go back and mount the tail and do some more work on the fuselage now.
Mar 05, 2009, 01:28 PM
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jsfrench's Avatar
This is looking good. For a distraction, some photos for you next project:

Mar 05, 2009, 08:18 PM
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RyanPSU21's Avatar
Thanks very much for the link. You picked it correctly from my partially done plans. I hadn't seen a model of this plane done before until 2 nights ago someone posted a link to this guy the other night in the 257" B36 build thread in the electric giants section.

I'm taking a bit of distraction now and finishing my Cub and then I'll get back to this. Trying to get this done on time at my 1 hour a night pace has started feeling a bit too much like work and I'm at the point right now where I could finish it by the deadline but I'd be really rushing it and have to leave off several things I would like to do such as gear doors and vacumn forming the cockpit and nose and having some form of cockpit interior. I'm going to cover my Cub and get it flying in the next month and have one winter project completed and then come back to this.
Jun 18, 2009, 08:54 PM
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RyanPSU21's Avatar
My workshop painting task and rearranging is finished so I can get back to work on this now. Tonight I just did a little bit and drilled holes for motor mounts and cut out some cooling holes into one of the firewalls. Not much but it's a start again. There is a small chance this may fly this year but more then likely it will be in the air next year at this point.
Jul 13, 2009, 10:14 PM
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RyanPSU21's Avatar
I got a little bit of inspiration and made the tailwheel tonight. My metal working skills and tools aren't great so just bent wire for me and some sloppy soldering.

I also did some weight checking tonight just for a status check.
Wing 1lb 5oz
Fuse 13 oz
Belly and fin 2 oz
battery 1lb 6oz
motors + escs 1lb 8oz
retracts + air system + wheels 11oz

That totals 5lbs 13 oz

My guestimates for what is left.
5oz for covering
4oz for servos and rx
3oz for wiring
4 oz more wood
2oz misc electronics or more wiring
total 1lb 2oz more.

Total 6 lbs 15 oz or about 7lbs.
My planned flight weight is hoping to be under 8 lbs so I've still got a pound of error.
Jul 14, 2009, 07:55 AM
Wannabe B-26 pilot!
Matt Halton's Avatar
Build is looking good RyanPSU21. Subscribed.
Jul 23, 2009, 10:16 PM
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RyanPSU21's Avatar
A little more progress tonight and the last week or so. Got some blind nuts and bolts to mount the motors. I still need to get some 1/2" standoffs somewhere eventually.

Started planking the nacelles tonight. Got a bit done on one of them. I think I am finally starting to get the hang of the planking bit. I will do the motor testing soon but want to sheet the top halves of the nacelles to give some more structure to the motor mounts before running the motors up on them.
Jul 29, 2009, 09:37 PM
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RyanPSU21's Avatar
The nacelle planking continues. Tonight I cut up a bunch more wood to use for stripping. I've found this always and annoying task since I find the ruler is always slipping as I cut and I end up with a lot of really non-straight planks. Tonight I got smart and made a fixture on the worktable by pinning down some 3/8" strip stock to hold the ruler in place and a couple of more to give a guide for the wood depth. After this I plowed through 4 or 5 sheets of 3/32" pretty quick and should have plenty of strips to do the rest of the nacelles now.
Aug 11, 2009, 10:17 PM
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RyanPSU21's Avatar
I have the top halves of the nacelles planked now. Time to turn back to the power system and retracts before planking over the bottom half. I did the motor wiring tonight and soldered on a lot of bullet connectors. I still need to make a Y-adapter to join the 2 ESC's. After that it will be time to fire up the motors and make sure the whole thing works this way. Atleast I know which end to put the long wires this time so not making the same mistake as my B24.
Aug 11, 2009, 11:20 PM
What could possibly go wrong?
nickchud's Avatar
Nice work.

Is it best to have the ESCs close to the battery or close to the motors?

For multi-motors, I got one of these Battery Eliminators . Do you have a solution to the problem of getting reliable power/voltage for servos from the ESCs? I was originally intending to use 2 diodes so that I could connect both BECs from the two ESCs to get the full power to 5 servos. But I was advised not to try that because the BEC output from most ESCs is not reliable enough to cope with models larger than 25oz or so.


Last edited by nickchud; Aug 11, 2009 at 11:58 PM.
Aug 12, 2009, 06:17 AM
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RyanPSU21's Avatar
The correct way to long leads between motor and ESC. There is a good thread in general formum about it.

There are a bunch of others in the power systems forums and there is a good article out there somewhere by Astro Bob regarding this. It has to do with the impedence from the on-off switching that operates the ESC and the impedence of the motor being able to dampen the spikes on that end while capacitors are needed to dampen them on the battery side.

Neither of my ESC's have BEC's in them. I have a UBEC to use that will be upstream of both ESC's in the wiring. There will be enough servos in this thing that it wouldn't have been a good idea to use most ESC BEC's anyways. They don't have overcurrent protections built in either so I will be adding some auto fuses to them as well.
Aug 12, 2009, 06:45 AM
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Kiwi's Avatar
The easy way to stop your ruler slipping when stripping planks is not to use a ruler, use the back of a hacksaw blade as a straight edge instead.The slight set on the teeth is just enough to grip into the balsa and stop it moving.

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