HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Oct 09, 2012, 12:57 PM
Registered User
Frans Bal's Avatar
Vlaardingen, The Netherlands
Joined Feb 2004
629 Posts
This is the list for the solid version.
You need a little extra 0.8 ply and 5mm balsa
Only one 12x100x1000mm sheet of balsa, weight approx, 140-150 gram. not 2 of 100 gram
Lightweight covering material
Some UD carbon for wing joints
Frans Bal is offline Find More Posts by Frans Bal
Reply With Quote
Sign up now
to remove ads between posts
Old Oct 09, 2012, 01:39 PM
Registered User
Joined Oct 2012
7 Posts
Hi all

I`m going to build a MiMi in the next time, I recieved the plans but still
a few questions remain.
I haven`t read the whole thread, it`s just too much, I hope you aren`t tired
to answer questions yet.

Im going to build the poly wing, have I to reinforce the two outer seams with
plywood or is it just the middle one?

The wing is 170mm deep, but my balsa is just 100mm, should I just glue them together with epoxy?
I suppose IŽll get in trouble with sanding then.

The tiled plan is just for the semi-solid, can I also use it for the solid wing?
Thank you,

Greets Nathanael
NathLee is offline Find More Posts by NathLee
Last edited by NathLee; Oct 09, 2012 at 01:46 PM.
Reply With Quote
Old Oct 09, 2012, 02:09 PM
Registered User
Frans Bal's Avatar
Vlaardingen, The Netherlands
Joined Feb 2004
629 Posts
Quote:
I am going to build the poly wing, have I to reinforce the two outer seams with plywood or is it just the middle one?
Yes only the middle one.
The seam of the inner and tip panel is reinforced with some glass fibre.
http://www.f3k.nl/index.php?id=127&page=3

Quote:
The wing is 170mm deep, but my balsa is just 100mm, should I just glue them together with epoxy? I suppose IŽll get in trouble with sanding then.
Best to use thick CA.
Any glue that can be sanded when dry can be used. some people use Titebond II wood glue, or UHU hart. (balsa cement)
http://www.f3k.nl/index.php?id=59

Quote:
The tiled plan is just for the semi-solid, can I also use it for the solid wing?
Yes you can. All poly wing shapes are the same.

Frans
Frans Bal is offline Find More Posts by Frans Bal
Reply With Quote
Old Oct 10, 2012, 10:12 AM
Registered User
Joined Oct 2012
7 Posts
Hi

Thank you, I suppose 49gm/m2 glass cloth will work
great for wing and fuse reinforcement.
But another problem just appeared, my 2 local balsa suppliers just
have 10mm thick balsa, the next thicker is 15mm.
Is there a chance to build the wing with just 10mm balsa without
loosing any good flying qualities?

Greets
NathLee is offline Find More Posts by NathLee
Reply With Quote
Old Oct 10, 2012, 11:47 AM
Registered User
Frans Bal's Avatar
Vlaardingen, The Netherlands
Joined Feb 2004
629 Posts
The thickness of the balsa has nothing to do with the weight/quality/performance
Just take 9 gram per mm (100x1000 mm sheet) for the solid wing.
and 12 gram per mm for the semi-solid wing.
The wing is a fraction thicker than 10 mm.
You can use a 10 mm thick sheet, fist roughly shape the wing.
At the root you probably will miss a Little balsa, just glue an extra piece of balsa in this position (make sure the bond is 100%) and sand the wing to shape.
The seam is visible, that's all.

Frans
Frans Bal is offline Find More Posts by Frans Bal
Reply With Quote
Old Oct 10, 2012, 11:58 AM
Registered User
Joined Oct 2012
7 Posts
Just thought about a thinner airfoil because of the missing balsa, but I`ll
just add a thin sheet on top like you said, hope it sticks well enough and doesn`t get ripped off while sanding...
Thank you for your support, you were very patient and answered every question in this long thread, thats not a matter of course

Greets
NathLee is offline Find More Posts by NathLee
Reply With Quote
Old Oct 10, 2012, 12:05 PM
Registered User
Frans Bal's Avatar
Vlaardingen, The Netherlands
Joined Feb 2004
629 Posts
To get a good bond just apply the glue evenly on both sides and press on firmly during drying.
Frans Bal is offline Find More Posts by Frans Bal
Reply With Quote
Old Oct 12, 2012, 04:36 AM
Registered User
Joined Oct 2012
7 Posts
Hey

I finished cutting and sanding the wing now, but they aren`t glued together yet.
Is there an alternative finish to PU laquer? Maybe a thin coat of laminating epoxy?

Greets
NathLee is offline Find More Posts by NathLee
Reply With Quote
Old Oct 12, 2012, 09:24 AM
LSFIII working on LVL IV
enrico74ec's Avatar
USA, FL, Daytona Beach
Joined Dec 2003
603 Posts
Frans,
I was looking at the pictures from your site and I saw that you where using some sort of liquid brushed on to the balsa and to finish the glass. Was that Water based varnish or laminating epoxy?

So far I got to weight 7 planks of balsa of 10 mm thick. I will have to add a little piece at the root to get it to 12 mm but it will be fine. The balsa I have come to a weight starting from 84.3 grams to 137 grams. I know is obvious to choose the lighter one but choosing and intermediate would have some benefit?

Thanks

Enrico
enrico74ec is offline Find More Posts by enrico74ec
Reply With Quote
Old Oct 12, 2012, 09:37 AM
Registered User
Joined Oct 2012
7 Posts
Hey Enrico, a short interposed question, how did you finish the balsa?
Is it even necessary to put anything on?
NathLee is offline Find More Posts by NathLee
Reply With Quote
Old Oct 12, 2012, 10:33 AM
LSFIII working on LVL IV
enrico74ec's Avatar
USA, FL, Daytona Beach
Joined Dec 2003
603 Posts
It depends but I do suggest you finish the balsa by sealing it or sealing and applying color paint. Also you can cover it with cover lite. this will give durability and impermeability to the wood.

My first MiMi built I finished the wing with dope, but I was in a hurry to fly so it was a heavy job. Now I am taking my time and building 2 MiMi, one regular per plans and a super lite MiMi using the semi solid wing. the super lite is an experiment. 1200 mm stretched wing, semi solid construction. Only reason I am going to try it is because my old MiMi has a 1m wing and a 1.2 m wing. The 1 m version weights 250 grms the 1.2 weights 300 grms. the stretched version is great for calm up to 9 mph winds, the 1 m version is great for 9 mph winds and up. No ballast needed up to 14 mph winds, after that, it just doesn't make sense to fly!
dead air times are 55sec to 1 min with the 1m version, 1min30sec with the stretched version.

She stays in my trunk with a special thermal shilding I made. I got a quick charger for the radio and lipo and I am always ready to fly! A two hour sesion (flying non stop) uses 55 mah of the 430 mah 1s lipo. Best deal ever!

Sorry, I think I went beyond answering your question, is just that is so much fun talking about the MiMi you get carried away!

Enrico
enrico74ec is offline Find More Posts by enrico74ec
Reply With Quote
Old Oct 12, 2012, 01:50 PM
Registered User
Frans Bal's Avatar
Vlaardingen, The Netherlands
Joined Feb 2004
629 Posts
Quote:
I finished cutting and sanding the wing now, but they aren`t glued together yet.
Is there an alternative finish to PU laquer? Maybe a thin coat of laminating epoxy?
Quote:
I was looking at the pictures from your site and I saw that you where using some sort of liquid brushed on to the balsa and to finish the glass. Was that Water based varnish or laminating epoxy?
I used solvent based PU varnish. Brush it on quite thick and wipe of with a rag.
Apply at least 3 coats.
Haven't used water based Pu varnish jet, so I don't now if the water part will warp the wood.

Laminating epoxy? I think it will do the job. Be aware not to put on to much.
Wipe of access epoxy thoroughly.

Quote:
So far I got to weight 7 planks of balsa of 10 mm thick. I will have to add a little piece at the root to get it to 12 mm but it will be fine. The balsa I have come to a weight starting from 84.3 grams to 137 grams. I know is obvious to choose the lighter one but choosing and intermediate would have some benefit?
Light balsa wood also tends to be soft and not that strong.
Better to use a more firm sheet that weighs a little more.
On a 10mm sheet I would not go heavier than 100 gram

Frans
Frans Bal is offline Find More Posts by Frans Bal
Reply With Quote
Old Oct 13, 2012, 02:57 AM
Registered User
Joined Oct 2012
7 Posts
I put now water based varnish on my wing, thought you also used water based(havent read your comment yet). Now the whole trailing edge wardped upwards for about 3 mm, I'm pretty sad now, dont know how to fix this properly, has anyone an Idea?

Greets
NathLee is offline Find More Posts by NathLee
Reply With Quote
Old Oct 13, 2012, 04:45 AM
Registered User
Frans Bal's Avatar
Vlaardingen, The Netherlands
Joined Feb 2004
629 Posts
Did you put the varnish on top and bottom in one go?
Frans Bal is offline Find More Posts by Frans Bal
Reply With Quote
Old Oct 13, 2012, 05:54 AM
Registered User
Joined Oct 2012
7 Posts
I first put on the upper side and 10 minutes later on the bottom, maybe that was the problem. I probably should have used grain filler that the varnish doesn`t get drew to much into the wood.

I tried to fix it with the hot air gun, it worked nod bad at all, I think I`ll get it straight after a few more tries...
Another question: How thin should the trailing edge be? I sanded mine not as thin as the airfoil jig is, mine is about 1mm






Greets
NathLee is offline Find More Posts by NathLee
Last edited by NathLee; Oct 13, 2012 at 07:03 AM.
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
1 meter electric sail plane Havens54 Electric Sailplanes 4 Apr 02, 2014 09:49 PM
1 meter mini IFO? Fantam Parkflyers 24 Nov 07, 2002 09:53 PM
Mini Pencam 1.3 in the UK? Mike_Y Parkflyers 12 Sep 20, 2002 01:20 PM
Mini Pencam 1.3 gooster Parkflyers 1 Sep 16, 2002 09:02 PM
WTB- Aiptek Mini PenCam 1.3 for aerial photography gooster Aircraft - Electric - Airplanes (FS/W) 2 Sep 13, 2002 11:38 PM