HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Jun 10, 2011, 05:28 AM
Registered User
slebetman's Avatar
Malaysia, Selangor, Kajang
Joined Jun 2009
1,452 Posts
Build Log
Pitty - Pitts inspired 24 inch bipe, with plans!

About a month ago someone flew a Pitts Special above my house. The real thing, not RC. I loved the way she looked in the sky. It's the first time I've seen a real life biplane. About two weeks ago she made another appearance and this time she did loops and rolls. It was then that I decided that I had to have a biplane in my fleet.

So roughly two weeks ago I built a profile bipe and crashed it several times before I got all the proportions right. This is a full fuse version of that final configuration. It is inspired by the Pitts but is not a Pitts. I didn't like the looks of the tail section on a real Pitts so I made my own. Then I had to redesign the wing tips to match the tail.

UPDATE:

There are two versions of plans: the full plan and the half plan. They are identical except that the half plan requires you to manually mirror the templates. Both plans are available tiled to A4 and US Letter.

Target weight for the build should be around 200g to 250g. Recommended motor is the AX 1806N 2100kv brushless. But any 20g brushless motor should do fine. Recommended battery for the target weight should be around 600mAh 2S or 400mAh-500mAh 3S.
slebetman is online now Find More Posts by slebetman
Last edited by slebetman; Jun 21, 2011 at 10:56 PM.
Reply With Quote
Sign up now
to remove ads between posts
Old Jun 10, 2011, 06:42 AM
It's Just Foam!!!
EZglider's Avatar
Canton,Ga
Joined Apr 2010
948 Posts
Looks good! Got any pics/videos of the finished plane? Also specs and what pwr system you're using would be helpful. Nice looking plans, this one is going on the Bipe-To-Do list.
EZglider is offline Find More Posts by EZglider
Reply With Quote
Old Jun 10, 2011, 08:58 AM
Registered User
slebetman's Avatar
Malaysia, Selangor, Kajang
Joined Jun 2009
1,452 Posts
Quote:
Originally Posted by EZglider View Post
Looks good! Got any pics/videos of the finished plane? Also specs and what pwr system you're using would be helpful.
Thanks. I don't have a picture of the finished plane because I'm in the middle of the build . Don't worry though, this is going to be a quick build. I'm hoping to maiden it on Sunday.

Here are some pictures of the build progress:
slebetman is online now Find More Posts by slebetman
Reply With Quote
Old Jun 10, 2011, 09:12 AM
Registered User
slebetman's Avatar
Malaysia, Selangor, Kajang
Joined Jun 2009
1,452 Posts
OK, got the depron pieces cut. I decided to try dry fitting them before gluing. Good thing I did because I realised the slots for the cabane struts are too narrow.

What happened was that I originally designed the fuse to be very narrow, to help when knife edging. Then I thought it looked too much like a profile plane with the narrow fuse so I broadened it a little. But I forgot to also broaden the center section of the wings. So now the cabane won't fit.

I don't really feel like making another set of wings so I'll either have to revert back to the narrow fuse or modify the current set of wings. Whatever I decide, I'll have to correct the plans. So I'm removing the plans for now until I've made the correction.
slebetman is online now Find More Posts by slebetman
Reply With Quote
Old Jun 10, 2011, 10:52 AM
Foam Av8r
RogueTitan's Avatar
In Teh Garage (Rossville, GA. USA)
Joined Sep 2008
3,351 Posts
looks pretty good IMO
RogueTitan is offline Find More Posts by RogueTitan
Reply With Quote
Old Jun 10, 2011, 11:08 AM
Registered User
United States, MN
Joined Feb 2011
4,377 Posts
nice looking plane so far, think i'll have to build one when you are done.
grimbeaver is offline Find More Posts by grimbeaver
Reply With Quote
Old Jun 10, 2011, 12:04 PM
Registered User
slebetman's Avatar
Malaysia, Selangor, Kajang
Joined Jun 2009
1,452 Posts
OK, I've decided to go with the narrower fuse since that requires the least amount of modifications to the current plans and it doesn't look too different.

I've also updated the rudder to look a little more roundish. I think it looks better now.

So plans are updated. I still think the plans need a little tweaking as I have found attaching the tail landing skid to be a little difficult. But basically I'm satisfied with the design overall.

Next is to do the hinges and install the control horns.
slebetman is online now Find More Posts by slebetman
Reply With Quote
Old Jun 10, 2011, 04:06 PM
ExPat
Aero Andy's Avatar
Spain, Murcia, Mazarrón
Joined Apr 2010
1,600 Posts
Good looking Pitts, great job on the build so far.
Andy
Aero Andy is online now Find More Posts by Aero Andy
Reply With Quote
Old Jun 10, 2011, 04:15 PM
Registered User
Joined Nov 2005
675 Posts
Looks good. I cant wait to see the maiden video. I will be building this for sure. Keep up the good work and please keep us posted

Reaper
soulreaper is offline Find More Posts by soulreaper
Reply With Quote
Old Jun 11, 2011, 06:45 AM
Registered User
slebetman's Avatar
Malaysia, Selangor, Kajang
Joined Jun 2009
1,452 Posts
Thanks for the words of encouragement guys. Means a lot to me.

So, the last thing I did last night was to hinge the control surfaces. I use tape hinges but done slightly differently than how I see others do it.

One problem I've had in the past with tape hinges is that the tape tends to come off the depron after some time. My solution to that is to cut a grove for the hinges but not all the way through. That leaves the shiny 'skin' of the depron uncut which protects the tape from becoming unstuck. I then tape the inside of the grove with masking tape to protect it. I find masking tape sticks better to cut or sanded depron.

Of course if you have glass tape then maybe all the above isn't necessary but I'm a cheapskate and packing tape is cheaper :P

I've tried hot glue hinges but the quality of the hinge depends on the glue. When I use the bendy, more rubbery glue then the hinge works well but when I use the harder, more brittle glue then it tends to break. The problem for me is that around here the glue are typically sold unbranded and even from the same store you sometimes get one type and sometimes the other. I just can't depend on the quality of the glue sticks around here and I don't like depending on luck.

Anyway, here are some progress pics:
slebetman is online now Find More Posts by slebetman
Reply With Quote
Old Jun 11, 2011, 07:25 AM
Registered User
slebetman's Avatar
Malaysia, Selangor, Kajang
Joined Jun 2009
1,452 Posts
This morning I started some work on the internal structure of the fuse. Some of the bits in this part of the build isn't on the plans at the moment because I find it easier for me to design and solve problems when I have the actual 3D structure in my hands. Don't worry though, I'll update the plans later to include them.

The structure is basically similar to a monoblock but is built-up instead of carved out. The internal structure is really minimal and I depend mostly on the skin to provide most of the support. Basically a monocoque construction. At this size 3mm depron is strong enough but any larger and we'd need more structure.

Currently the AUW is around 172g. That's just 28g shy of my target weight of 200g. I'm still hopeful that I'd be able to reach that target.

Now I'll have to install the control horns. Have to do it now if I want to maiden this tomorrow morning since the epoxy takes 12 hours to cure.
slebetman is online now Find More Posts by slebetman
Reply With Quote
Old Jun 11, 2011, 10:39 AM
tree scavenger
USA, OH, Cincinnati
Joined Sep 2006
585 Posts
oh very Nice!

...been wanting to do a semi-Pitts too,,
i think i have everything....cept the skills!? hehe
how'd you make the lightening holes?
...really liking the looks of her so far
silentsurfer is offline Find More Posts by silentsurfer
Reply With Quote
Old Jun 11, 2011, 11:40 AM
Registered User
slebetman's Avatar
Malaysia, Selangor, Kajang
Joined Jun 2009
1,452 Posts
Quote:
Originally Posted by silentsurfer View Post
...been wanting to do a semi-Pitts too,,
i think i have everything....cept the skills!? hehe
how'd you make the lightening holes?
...really liking the looks of her so far
Thanks. The holes were simply cut out with an x-acto knife and then smoothed out using a round file.

Unfortunately I made a mistake with the servo placement. The casing of the higher servo blocks the movement of the sunken servo. The good news is that it isn't too much work to redo the whole thing. The bad news is the setback may mean that I wouldn't finish her by tomorrow morning and will have to wait for next weekend to maiden her.

Still, not a big deal but I'm not good at waiting.
slebetman is online now Find More Posts by slebetman
Reply With Quote
Old Jun 12, 2011, 02:39 AM
Registered User
slebetman's Avatar
Malaysia, Selangor, Kajang
Joined Jun 2009
1,452 Posts
OK so it's official, I wouldn't be able to maiden her this weekend. Which means a week of waiting for me. On the plus side, this means that I have more time to build. I'm already sort of regretting rushing through the rebuild of the internal framework - it caused too many imperfections.

The servos are now installed inline. Looking at it now it looks like the most obvious way to do it. But it actually took me a while to figure it out.

Forgot to mention this before: for this build I'm using mostly hotglue except for the installation of the control horns which I used epoxy.
slebetman is online now Find More Posts by slebetman
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Build Log Shorts Skyvan 24 inch - test flight video gklein Scratchbuilt Indoor and Micro Models 65 May 01, 2011 10:51 AM
Found Cowl from HobbyKing Pitts-EP 42 inch ARF djmoose Aircraft - Electric - Airplanes (FS/W) 2 Apr 04, 2011 11:28 PM
Wanted WTB Herr 24" Pitts plans swapinthedark Aircraft - Electric - Airplanes (FS/W) 1 Mar 30, 2010 02:02 PM
Wanted WTB plans for the Herr 24" Pitts bipe. swapinthedark Aircraft - Electric - Micro & Indoor Airplanes (FS/W) 0 Mar 29, 2010 10:00 PM
Discussion 24, 30, or 35 inch shoestring kit or plans? paulatgis Sport Planes 4 Nov 01, 2009 06:32 PM