By continuing to use this site, you agree to our use of cookies. Find out more
Forum sponsored by:
Forum sponsored by CML

Oodalally

My latest quickie design

All Topics | Latest Posts

Search for:  in Thread Title in  

Articles

RCM&E April 2013 issue preview!

RCM&E April 2013 issue preview!

in the shops 8th March

Peter Miller09/04/2013 08:24:45
avatar
9850 forum posts
1157 photos
10 articles

Looking very nice indeed.

Peter Miller09/04/2013 09:51:34
avatar
9850 forum posts
1157 photos
10 articles

Time for me to eat humble pie again.

Just checked the plan in RCM&E and the ribs are as per my origincal drawing in thickness but they do vary in length slightly. My aopolies. Not sure how I thought they had not been corrected.

I think I may have checked agains the proof plan again instead of the magazime plan. Senility is galloping in.

kc09/04/2013 11:54:57
5872 forum posts
168 photos

Making new ribs might be an answer, bearing in mind that with a tapered wing only the largest rib needs a new bit of balsa, the next one down can use the biggest old rib trimmed down and so on.

eg. in this case then R2 is made from new balsa, R3 uses the old R2 trimmed down etc. Saves balsa and makes a first class job!

kc09/04/2013 12:16:20
5872 forum posts
168 photos

I have just realised that all the ribs that were incorrect are those which are drawn horizontal and those drawn vertical are OK. This suggests an error in photocopying where they distort in one direction only. Something has perhaps happened in fitting all the parts in on the plan. Those drawn in the same way as the wing distort in a way compatible with the wing!

Piers Bowlan09/04/2013 13:06:48
avatar
1755 forum posts
42 photos

Perhaps next months mag could have the errant ribs drawn correctly within its pages rather than reprinting the whole plan which is not necessary. It would reassure prospective builders who might have seconds thoughts about starting a project where there is a known issue with part of the drawing.

No need to eat humble pie Peter, it was a minor printing error. Not your department!

Peter Miller09/04/2013 13:38:26
avatar
9850 forum posts
1157 photos
10 articles

No, I said that the ribs were too narrow, i.e 11% instead of 13%. I was wroing, The plan in the mag is fine as regards to width.

As for the variation in length. I would either trim them all to a straight line por just pack them out to the leadign edge with scrap.

AJ09/04/2013 17:01:23
143 forum posts
12 photos

If the problem is just in the copying process does this suggest that it could also be corrected photographically by applying the right amount of stretch in an appropriate direction when copying the plans? Bit like the Hubble solution!

My issue is determining the correct shape for the extended ribs, if I just add a bit at the end I will have a concave profile where it is added, to my mind it needs size adding all the way down the curve of the rib to work properly.

 

Edited By Andrew Eastland on 09/04/2013 17:11:21

Peter Miller09/04/2013 18:05:02
avatar
9850 forum posts
1157 photos
10 articles

The profile on the ribs on the plan in the magazine is correct. You don't have to do anything to them.

There are very slight differences in the length but nothing to worry about

Richard scarborough10/04/2013 09:35:13
46 forum posts
41 photos

I have built the wing and didn't have any problems. I believe the plan to be correct.

Cheers, Richard.

AJ10/04/2013 10:50:06
143 forum posts
12 photos

Hi Richard, how did you overcome the size diferrences with R1 to R4? ie where did you add the missing 2mm or did you reposition the le or te to fit?

Also how did you assemble the le sheet? The cross section at the root shows the top and bottom sheet butting up to the rear of the le but the cross section at the bell crank shows it on the top/bottom of the le. I can't work out from the plan view how this is possible or if one or the other is correct, how did you do it?

Sorry if I am missing something obvious here but this is my first build from a plan, I have always done kits before this so I am struggling a bit to work some of it out.

Andew

kc10/04/2013 11:03:10
5872 forum posts
168 photos

It is good to know that the wing can be built OK from the plan but it is wrong to say the plan is "correct" Anyone with a ruler can measure the ribs ( on rib shapes and then on wing plan ) and see that Andrew is correct in his measurements.

I am sure the LE sheeting goes over the LE 1/8 all the way along and is capped after glue is dry with another layer of 1/8 which is stronger than the butt joint which would result from the root rib ( incorrect ) drawing .

Actually this is always a problem, if you make any mistake in cutting out ribs they dont quite meet the TE. Some designs, like this one, use sheeting above and below which makes a firm joint. In other cases it can be handy to increase the rib lengths and inset them into TE.

Edited By kc on 10/04/2013 11:15:41

Peter Miller10/04/2013 11:27:48
avatar
9850 forum posts
1157 photos
10 articles
Posted by Andrew Eastland on 10/04/2013 10:50:06:

Also how did you assemble the le sheet? The cross section at the root shows the top and bottom sheet butting up to the rear of the le but the cross section at the bell crank shows it on the top/bottom of the le. I can't work out from the plan view how this is possible or if one or the other is correct, how did you do it?

Sorry if I am missing something obvious here but this is my first build from a plan, I have always done kits before this so I am struggling a bit to work some of it out.

Andew

The leading edge is made with two pieces of 1/8 sheet. The first is stuck to the ribs before sheeting, the second is stuck over the front of the wing after sheeting. This forms a rebate in theleading edge. Stronger, neater, easier.

Richard scarborough10/04/2013 13:30:40
46 forum posts
41 photos

Andrew, the method I used is this, cut out the ribs as per plan but leave a couple of mm on each end.Pin down the main spar and trailing edge. When you try to place the rib over the spar you can see how much needs to be cut/sanded from the back of each rib to get a good fit. With the leading edge, you can now trim the front of the ribs so they line up with the L/E drawn on the plan. Now glue the ribs to T/E and spar. When that has dried, bevel and glue on the L/E. Now is a good time to glue in the top spar.

The L/E sheet goes over the 1/8 L/E. The 1/8 L/E capping covers both. You will need to cut the sheet wide enough to extend just past the 1/8 L/E so it can be sanded back flush.

Whenever I cut out parts from any plan I always leave a bit of extra material on edges that must fit exactly, and then sand carefully until they do fit.

Hope this helps, Cheers, Richard

AJ17/04/2013 11:36:19
143 forum posts
12 photos

LH wing is now built. Just starting on the RH. Thanks for all the help and suggestions. I finally went with Richard's method, the instructions in the mag just don't make sense until after you've built one.

Fus is complete with an electric conversion, added a second firewall half way down the engine bay. One issue left, how do you get the screen to stick onto solarfilm? Don't think there is a glue that will bond perspex to film, suspect I will need to cut back to bare wood to get a secure fixing, or alternatly drill and screws?

kc17/04/2013 12:20:31
5872 forum posts
168 photos

I think the easiest way to fit a windscreen is to leave 2 or 3 'tabs' on the bottom of the windscreen and insert them into slots ( just a scalpel pushed in ) in the balsa after covering. A dab of glue on the tabs will secure.

Peter Miller17/04/2013 18:40:51
avatar
9850 forum posts
1157 photos
10 articles

I use very small screws to hold the windscreens down, then I seal it with canopy glue, either Zap or MD products

Jim Carss17/04/2013 18:42:00
avatar
2052 forum posts
73 photos

As KC says, this is the way to do it

 

Edited By Jim Carss on 17/04/2013 18:42:39

AJ18/04/2013 00:13:08
143 forum posts
12 photos

Screen problem solved, hot melt glue gun. Sticks to both the solarfilm and the perspex like the proverbial...

Like the tab solution, will try this next time, when the film rips off from the balsa probably . Had already made the screen without tabs so too late for this one.

Terry Walters08/05/2013 21:29:44
avatar
1831 forum posts
1068 photos

Well what have I been doing today?

Just made a complete set of wing ribs for the Oodalally. I've got so many projects on the go I couldn't face any of them so it was a very nice therapy to just do something different! Thank you Peter Miller!

Going to make all the formers tomorrow or Friday (weather dependent!) and then we'll see how far I can get with my stock without having to buy anything! I suspect it will t/e profile that will scupper me!

Terry

Peter Miller09/05/2013 08:16:11
avatar
9850 forum posts
1157 photos
10 articles

Just shape the T.E. from thick sheet...or are you out of that as well?

Have fun!

All Topics | Latest Posts

Please login to post a reply.

Magazine Locator

Want the latest issue of RCM&E? Use our magazine locator link to find your nearest stockist!

Find RCM&E! 

Support Our Partners
Wings & Wheels 2019
Pepe Aircraft
CML
Revoc
electricwingman 2017
Slec
Gliders Distribution
Motion RC
Sarik
Advertise With Us
Latest "For Sale" Ads
Does your club have a safety officer?
Q: Does your club have a safety officer, or is the emphasis on individual members to each be their own safety officer?

 Yes we have a SO
 No, it's down to everyone

Latest Reviews
Digital Back Issues

RCM&E Digital Back Issues

Contact us

Contact us