HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Feb 06, 2011, 07:31 PM
Taranis Tyro...
MattyB's Avatar
United Kingdom, England, Hitchin
Joined Jan 2004
3,786 Posts
Build Log
Limit EX ISA mass build

EDIT March 1st 2011 - Added Limit Mk1 and Mk3 plans to first post, along with revised ribset for Mk1 (several people have asked about getting the plan since we started this project). Following the successful first flights of our foam winged Limits I've attached the templates used (E374, 8% at root, 9% at tip with 1 degree of washout) for anyone who wants to try them.

EDIT August 8th 2011 - For those interested in vac bagging with a nebulizer, my first tests are here and the first parts can be seen here and here.

EDIT April 10th 2012 - Reports and pics of our mass flight day are here.


EDIT June 6th 2012 - Attached 2x scale Limit Mk1 plans and ribs.



Inspired by the many team build threads here on RC Groups, me and a few members of our club (the Ivinghoe Soaring Association) have decided to take on a mass build of our own. After extensive debate and deliberation we agreed on the Limit EX as our subject...


Today things got started in earnest as I blocked out all the wing panels. The builds will all be different - most are going with a foam wing and balsa fuse, but a few are sticking with balsa throughout and I'll be trying a lost foam fuse based on Samotage's build .

Anyway, here are the first few pics; considering this was the first time I'd wielded a bow, I was pretty pleased with the results (only one unusable blank, which luckily is still big enough to become my fuse plug). Next up is the manufacture of the templates (section tbd, but it will be more symmetrical than the one on the plan), cutting my fuse plug, then assembly line wing cutting and linkage manufacture at our club night on Feb 16th. Enjoy!
MattyB is online now Find More Posts by MattyB
RCG Plus Member
Last edited by MattyB; Jan 07, 2014 at 01:53 PM. Reason: Added 2x scale plans and ribs
Reply With Quote
Sign up now
to remove ads between posts
Old Feb 06, 2011, 09:17 PM
Registered User
Joined Aug 2005
2,689 Posts
DT56 is offline Find More Posts by DT56
Reply With Quote
Old Feb 07, 2011, 11:19 AM
Taranis Tyro...
MattyB's Avatar
United Kingdom, England, Hitchin
Joined Jan 2004
3,786 Posts
Some balsa bashing

Adrian from our team has gone storming ahead with his all balsa build; some pics from his Flickr stream are attached...

Slow down man, you're putting the rest of us to shame!
MattyB is online now Find More Posts by MattyB
RCG Plus Member
Latest blog entry: EFX Racer
Reply With Quote
Old Feb 07, 2011, 11:36 AM
.....till the wind drops.
Sean Oelofse's Avatar
Port Elizabeth, South Africa
Joined Oct 2006
3,556 Posts
Howzit MattyB !!??
Great choice of plane from the ISA members!
Seems Adrian wants this build over and out the way!!
Did'nt think I would make this comment at post #4 ..... ... anyway.... tell Adrian to keep the rates as per drawing!......low!

Sean Oelofse is online now Find More Posts by Sean Oelofse
Reply With Quote
Old Feb 07, 2011, 04:08 PM
SB-28 UK Display Pilot
GeeW's Avatar
ENGLAND
Joined Jul 2001
2,463 Posts
Sean
Spoilsport!

Brill little slope model, my Limit EX Mk3 is always packed for trips to the slope.
GeeW is online now Find More Posts by GeeW
Reply With Quote
Old Feb 08, 2011, 07:32 PM
Taranis Tyro...
MattyB's Avatar
United Kingdom, England, Hitchin
Joined Jan 2004
3,786 Posts
A question of sections...

For the foam winged versions we are trying to decide between MH42 and E374 (we know the original foils are good, but are happy to sacrifice some soaring capability for a bit more inverted performance - several people have told me this is where the original wing loses out). Any thoughts on which is the best choice?
MattyB is online now Find More Posts by MattyB
RCG Plus Member
Last edited by MattyB; Feb 08, 2011 at 07:43 PM.
Reply With Quote
Old Feb 08, 2011, 09:01 PM
Embrace the suck
nauga's Avatar
Joined Nov 2004
4,269 Posts
This is a cool idea - I'd love to see a pic of a mass launch.

Quote:
Originally Posted by MattyB View Post
For the foam winged versions we are trying to decide between MH42 and E374 [...] Any thoughts on which is the best choice?
With an aspect ratio of something like 6 and near single-digit Reynolds numbers (a slight exaggeration, I know ) I'm going to suggest that the airfoil choice doesn't matter a whole lot. I'm sure some will disagree.

Nauga,
who is certain about uncertainty
nauga is offline Find More Posts by nauga
Reply With Quote
Old Feb 09, 2011, 04:23 AM
Taranis Tyro...
MattyB's Avatar
United Kingdom, England, Hitchin
Joined Jan 2004
3,786 Posts
Quote:
Originally Posted by nauga View Post
With an aspect ratio of something like 6 and near single-digit Reynolds numbers (a slight exaggeration, I know ) I'm going to suggest that the airfoil choice doesn't matter a whole lot. I'm sure some will disagree.
Yeah, I'm inclined to agree Nauga, but it's nice to have it confirmed by someone such as yourself with much greater aero knowledge. One option I am now thinking about is a Kline Fogleman (KF) airfoil - they are easy to construct, and as you point out their disadvantages may not be so big at these sizes. Some research required methinks...
MattyB is online now Find More Posts by MattyB
RCG Plus Member
Last edited by MattyB; Feb 09, 2011 at 04:43 AM.
Reply With Quote
Old Feb 09, 2011, 01:33 PM
SB-28 UK Display Pilot
GeeW's Avatar
ENGLAND
Joined Jul 2001
2,463 Posts
The main problem with the KF airfoils is the very limited speed range they work over in practice. I admit I have only ever built and flown one KF airfoiled glider. At slow to medium speeds it's performance was better than I had expected. Flight at higher speed was disappointing.
The original airfoil (which probably came from the outside edge of Mr B's right shoe) works very well. The Limit has an excellent speed range as standard, why risk bu@@ering it up?

http://www.sebrfc.org.uk/gallery/pub...ry_m.php?i=340
GeeW is online now Find More Posts by GeeW
Reply With Quote
Old Feb 09, 2011, 01:39 PM
SB-28 UK Display Pilot
GeeW's Avatar
ENGLAND
Joined Jul 2001
2,463 Posts
nauga
Love the "With an aspect ratio of something like 6 and near single-digit Reynolds numbers" LOL
GeeW is online now Find More Posts by GeeW
Reply With Quote
Old Feb 10, 2011, 09:57 AM
Taranis Tyro...
MattyB's Avatar
United Kingdom, England, Hitchin
Joined Jan 2004
3,786 Posts
Quote:
Originally Posted by GeeW View Post
The main problem with the KF airfoils is the very limited speed range they work over in practice. I admit I have only ever built and flown one KF airfoiled glider. At slow to medium speeds it's performance was better than I had expected. Flight at higher speed was disappointing.
OK, that's enough for me!; I guess the turbulent flow off the step generates huge amounts of drag as you speed up. Thanks for the info (I may still try a KF for an experiement in future, but it won't be the Limit).

Quote:
Originally Posted by GeeW View Post
The original airfoil (which probably came from the outside edge of Mr B's right shoe) works very well. The Limit has an excellent speed range as standard, why risk bu@@ering it up?
I kind of agree, but it's not speed or pinged pylon turns we're after; both the people I know who've built one said they loved the way it flew, but would have liked a bit more inverted performance (it does have a nearly flat bottomed aerofoil after all). One of them then built a fully symmetrical wing which was fun but didn't corner too well(!), hence why we're looking at these two well established aerobatics aerofoils.
MattyB is online now Find More Posts by MattyB
RCG Plus Member
Last edited by MattyB; Feb 10, 2011 at 10:03 AM.
Reply With Quote
Old Feb 10, 2011, 01:58 PM
Registered User
ian murdock's Avatar
United States, NV, Carson City
Joined Jan 2007
631 Posts
I have been looking into buliding this same glider, it looks like it might be an inexpensive build and fun fly.
ian murdock is offline Find More Posts by ian murdock
Reply With Quote
Old Feb 10, 2011, 01:58 PM
SB-28 UK Display Pilot
GeeW's Avatar
ENGLAND
Joined Jul 2001
2,463 Posts
I sort of agree on the inverted, a bit more would be nice.
I would advise increasing the tailplane span a bit. Think I added about 30mm to the total span ie 15mm/side on the recommendation of others.

ian murdock
It is an excellent sloper. Built mine in 3 evenings with another one to cover.
GeeW is online now Find More Posts by GeeW
Reply With Quote
Old Feb 10, 2011, 03:13 PM
Registered User
Joined Aug 2005
2,689 Posts
Quote:
Originally Posted by MattyB View Post
OK, that's enough for me!; I guess the turbulent flow off the step generates huge amounts of drag as you speed up. Thanks for the info (I may still try a KF for an experiement in future, but it won't be the Limit).


I kind of agree, but it's not speed or pinged pylon turns we're after; both the people I know who've built one said they loved the way it flew, but would have liked a bit more inverted performance (it does have a nearly flat bottomed aerofoil after all). One of them then built a fully symmetrical wing which was fun but didn't corner too well(!), hence why we're looking at these two well established aerobatics aerofoils.
If using dual aileron servos and a computer radio, a simple flaperon / elevator mix will make the symmetrical foil turn better. Also give you the ability for a crow mix if wanted.

Do you know what thickness foil the builder used on the symmetrical wing? I'm considering a larger version and would be interested in a symmetrical foil.
DT56 is offline Find More Posts by DT56
Reply With Quote
Old Feb 10, 2011, 10:14 PM
Registered User
ian murdock's Avatar
United States, NV, Carson City
Joined Jan 2007
631 Posts
WOW that fast. sweet now I have to look into this glider.
Quote:
Originally Posted by GeeW View Post
I sort of agree on the inverted, a bit more would be nice.
I would advise increasing the tailplane span a bit. Think I added about 30mm to the total span ie 15mm/side on the recommendation of others.

ian murdock
It is an excellent sloper. Built mine in 3 evenings with another one to cover.
ian murdock is offline Find More Posts by ian murdock
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Need limit ex plan. flybaby2000 Slope 140 Jan 10, 2013 01:50 PM
Discussion Ex Limit EX alexholt Slope 0 Jan 25, 2006 12:59 PM
Limit EX Build Questions DCS Slope 36 Nov 07, 2005 11:10 AM
Limit EX Woodie(crunchie) build fly1milehi Slope 47 Jan 24, 2005 02:36 PM
Limit Ex julianb Slope 2 Dec 16, 2004 05:52 PM