HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Jun 12, 2009, 07:13 AM
LSFIII working on LVL IV
enrico74ec's Avatar
USA, FL, Daytona Beach
Joined Dec 2003
603 Posts
Hi Frans, thanks for the tips, I will use the lighter fiberglass since it is just for peace of mind, security blanket I guess.

Last night after finding out the the pod was just too weak,i decided to glass it. I didn't know what I was up to until I got in to it. No matter how much you read and try to learn, you have to experience it first. Still drying but it will require extra work. I started with 2 oz. fiberglass from the cg forward just to see ifi can add weight structurally rather than on dead weight a.k.a nose lead. I did add a CF tow on each side of the pod. today i will have to sand,smooth everything out and then apply a second layer of .75 oz. to give it a smooth finish.

So far what i have learned with this:
- need to work more organized, prevents epoxy going everywhere
- cut your FG to the exact shape you need.
- Work small batches of epoxy at a time
- leave enough overlap on the top and bottom so it can give you about 1/8 to each side.
- sides need to be in line to the side outline
- cut,and i repeat cut flares of, don't pull them, it gets messy in a breeze!

Sorry i have no pictures,got a bit messy but will take some today.

On the bright side, pod #2 is inthe werks so i'll have a backup just in case this just too heavy, although at 110 gr, so far, I think 165 gr target is possible even with the glassed fuse.

Enrico
enrico74ec is online now Find More Posts by enrico74ec
Reply With Quote
Sign up now
to remove ads between posts
Old Jun 12, 2009, 05:15 PM
Registered User
Frans Bal's Avatar
Vlaardingen, The Netherlands
Joined Feb 2004
628 Posts
Hi Enrico

Quote:
- cut your FG to the exact shape you need.
If you glass the fuselage cut the fiberglass in a 45 degree bias.
Fiberglass can be draped around curves more easily this way.
You will only need one piece to do the whole fuse.


Quote:
- Work small batches of epoxy at a time
Did you put the fiberglass on with 5 min epoxy?
If you did, it's not the best way. There is to little time to get the glass on and it's to thick to soak the fibers.
Better you use laminating epoxy with a minimum pot life of an hour or so.
Or use PU-varnish. Cheap and easy to get at the local store.
I used it on my newest MiMi with all glass i put on, great stuff.

Frans
Frans Bal is offline Find More Posts by Frans Bal
Reply With Quote
Old Jun 13, 2009, 05:35 AM
Registered User
Joined Jun 2009
7 Posts
Hi all, Iím new to this DLG thing so sorry if what I am about to ask is a daft question. Does the tail boom for the Mimi need to be tapered or can I simply use a piece of carbon tube with a 1mm wall thickness, will this be too heavy? Also what wood densities should I be trying to obtain?

Thanks Ollie
Ollie B is offline Find More Posts by Ollie B
Reply With Quote
Old Jun 13, 2009, 08:02 AM
Lots of Air Play
United States, CT, Coventry
Joined Dec 2008
843 Posts
Quote:
Originally Posted by Ollie B
Hi all, Iím new to this DLG thing so sorry if what I am about to ask is a daft question. Does the tail boom for the Mimi need to be tapered or can I simply use a piece of carbon tube with a 1mm wall thickness, will this be too heavy? Also what wood densities should I be trying to obtain?

Thanks Ollie
Untapered is fine. I use a carbon fiber arrow shaft that I buy from a local sporting goods store, runs about $5. It's about 1/4" diameter, a Bemers Deerhunter 350, I ask for the stiffest arrowshaft that they have. I am sure that others can fill you in on their sources.

Dave in CT
thistle2311 is online now Find More Posts by thistle2311
Reply With Quote
Old Jun 13, 2009, 09:05 AM
Registered User
Frans Bal's Avatar
Vlaardingen, The Netherlands
Joined Feb 2004
628 Posts
Hi Ollie B,

Quote:
Also what wood densities should I be trying to obtain
Well getting the right wood can be the only difficult thing to do building a MiMi.
Try to get balsa that weighs less than 100 gram/dm3 or 6 lb/cu.
Lighter is better but be aware not to buy to soft balsa.
Look for light balsa with nice longitudinal grain that's not soft.
(1 lb/cu equals 16.018 gram/dm3.)

Quote:
can I simply use a piece of carbon tube with a 1mm wall thickness, will this be too heavy?
Yes you can...
But first weigh it and if the weight is more than something like 8 gram for 20" length try to get a lighter one.

Frans
Frans Bal is offline Find More Posts by Frans Bal
Reply With Quote
Old Jun 13, 2009, 01:51 PM
Registered User
Joined Jun 2009
7 Posts
Thanks guys, I went and got the wood today I think it is light enough, perhaps a bit on the heavy side but we'll see. They didn't have the right size carbon or the right wing bolt so need to get those and I should be sorted. Can't wait to get started now.

Ollie
Ollie B is offline Find More Posts by Ollie B
Reply With Quote
Old Jun 14, 2009, 09:24 PM
LSFIII working on LVL IV
enrico74ec's Avatar
USA, FL, Daytona Beach
Joined Dec 2003
603 Posts
Quote:
Originally Posted by Frans Bal
Did you put the fiberglass on with 5 min epoxy?
If you did, it's not the best way. There is to little time to get the glass on and it's to thick to soak the fibers.
Better you use laminating epoxy with a minimum pot life of an hour or so.
Or use PU-varnish. Cheap and easy to get at the local store.
I used it on my newest MiMi with all glass i put on, great stuff.

Frans

Hi Frans,

Actually i used Great Planes finishing resin. It gives you a pot life of about 45 minutes and then you can re - delute it with some acetone and it will give you a nice syrup consistency easy to wet out more fiberglass.

I have some low quality cell phone pictures from the first layer glassed but they show enough. I,ll take more pictures tomorrow of the sanded fuse ready for a second layer.

Enrico
enrico74ec is online now Find More Posts by enrico74ec
Reply With Quote
Old Jun 14, 2009, 11:37 PM
LSFIII working on LVL IV
enrico74ec's Avatar
USA, FL, Daytona Beach
Joined Dec 2003
603 Posts
A little more done tonight. Sanded fuse and tried to get all the roughs out, worked pretty well, and applied the 0.75 oz fiberglass to finish it smooth. So far, without the resin it is at 20 grms. Heres some pictures, enjoy

Enrico
enrico74ec is online now Find More Posts by enrico74ec
Reply With Quote
Old Jun 16, 2009, 02:41 PM
Registered User
Joined Jun 2009
7 Posts
Although to most of you this may well be second nature, I have still yet to find a quick and accurate way in which to cut out the ply rib sanding templates. I have also been struggling to find the best way to taper the control surfaces. Any advice greatly appreciated.

Thanks, Ollie
Ollie B is offline Find More Posts by Ollie B
Reply With Quote
Old Jun 16, 2009, 02:43 PM
Unshaven yokel
sparkysko's Avatar
Portland, Oregon
Joined Oct 2007
1,483 Posts
Jigsaw?

Or rough cut with a saw and then block sand with 60 grit?
sparkysko is offline Find More Posts by sparkysko
Reply With Quote
Old Jun 16, 2009, 03:11 PM
Lots of Air Play
United States, CT, Coventry
Joined Dec 2008
843 Posts
Cutting the Template Ribs

Quote:
Originally Posted by Ollie B
Although to most of you this may well be second nature, I have still yet to find a quick and accurate way in which to cut out the ply rib sanding templates. I have also been struggling to find the best way to taper the control surfaces. Any advice greatly appreciated.

Thanks, Ollie
I print out the template, spray a bit of 3M adhesive, and position it on 1/32 plywood. Then cut out carefully with a good sharp pair of scissors. Done!

Dave in CT
thistle2311 is online now Find More Posts by thistle2311
Reply With Quote
Old Jun 16, 2009, 03:53 PM
Registered User
Frans Bal's Avatar
Vlaardingen, The Netherlands
Joined Feb 2004
628 Posts
@Enrico,
Looks nice.
I see that you put a triangle fiberglass on the launching-tip.
To give this tip some extra strength it's better to put a 2" wide band over the tip.
It will give some extra body for gluing in the blade.
(see picture posted earlier)
You can also dilute the epoxy during mixing.
A little bit thinner epoxy is easier to put on.
Syrup consistency is a bit on the thick side.
Looks nice, keep it up.


@Ollie B,
Just like Dave wrote, stick a 1 : 1 copy on some plywood.
I use a jigsaw to roughly cut it out, than sand it to correct shape.


Frans
Frans Bal is offline Find More Posts by Frans Bal
Reply With Quote
Old Jun 16, 2009, 04:44 PM
Registered User
Joined Jun 2009
7 Posts
Thanks, I'll defiantly bare that in mine for the future but for now I think that I may have found an easier solution.

Ollie
Ollie B is offline Find More Posts by Ollie B
Reply With Quote
Old Jun 16, 2009, 05:10 PM
LSFIII working on LVL IV
enrico74ec's Avatar
USA, FL, Daytona Beach
Joined Dec 2003
603 Posts
Frans, thanks for the input. I did actually thin it to a low viscosity and was able to apply it with a brush. I will need to sand it though to get rid of all the voids and lumps but thats ok. I guess that would be the final step and sand it down to a very fine grit say 600 or so. that should give it a nice finish (or at least I hope) Only draw back is that takes longer to dry. O well, back to building #2.

Enrico
enrico74ec is online now Find More Posts by enrico74ec
Reply With Quote
Old Jun 16, 2009, 07:33 PM
Registered User
Joined Jan 2007
17 Posts
thank to your help I could finish my MIMI, See some pics, I was inspired by Ferrari red colour!

Even if it is heavy it flies very well and I love flying Mimi. The reason of the weight is the boom which is CF 8 mm and weights 17 gr. In fact I had to ballast 20 gr in order to have 6 cm CG from leading edge.

About weights:
-complet model without servos, receiver, battery (4x250 mAh= 32gr) and spring: 134 gr.
-Ready to fly model weight: 205 gr.

I tried to exclude ballast, CG now is more the 7 cm and elevator downward: I think it flies better. I will reduce the weight of the battery, eliminate oracover with PU varnish, make some holed in the wings. I'm thinking to build a longer pod top avoid ballast as well.

My advice is to reduce weight.
fillis is offline Find More Posts by fillis
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