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

Ballerina by EarlyBird

All Topics | Latest Posts

Search for:  in Thread Title in  
Peter Miller14/07/2020 13:24:26
avatar
11211 forum posts
1321 photos
10 articles

Many years ago I was told about a young lad in the Peterborough club whose partypiece was to attach a piece of chalk to the tip of his fin and draw lines down the runway.

The person who told me was learning to fly there and he would not be a line shooter

EarlyBird14/07/2020 16:33:58
186 forum posts
146 photos

I have learned today that cowls are not easy.

dscn0319.jpg

Keyholes cut in the mounting plate and test fitted

dscn0320.jpg

Three balsa sides cut to size

dscn0321.jpg

Leaving the bottom to sort out.

dscn0322 (2).jpg

As it is electric I will be using a ventilated spinner from 4-Max but as I never take any risks and following my dyed in the wool belt and braces approached I am redesigning the front to include a ventilation slot. As a few decisions are require progress could become even slower.

Steve

EarlyBird14/07/2020 16:37:17
186 forum posts
146 photos

Peter

Something else I have learned today is if I am feeling down I know to come on the forum to be cheered up.

smiley

Happy smiling Steve

Peter Miller14/07/2020 18:19:00
avatar
11211 forum posts
1321 photos
10 articles

One of the great things about building ones own models from plans is that one can add ones own ideas and modifications.

Sometimes it may not work. Never worry about that! One learns that way.

I always tell people that it is the first step to designing models.

On your model, fine. Just remember that an air outlet is just as important. The through flow of cooling air is what works.

EarlyBird15/07/2020 08:19:52
186 forum posts
146 photos

I had difficulty holding the three sides of the cowl in place so I could test fit and make adjustments.

So I cooked my dinner. While doing so I had one of those light bulb moments, we all have them, it's when I see the blindingly obvious.

I realised why others glue one piece on first and let it dry. This gives a firm foundation to build on. Checking other builds there is a tendency to start with the bottom and work up. Just to be different I have taken the top down approach.

Top fitted and glued then allowed to dry. Once dried one side fitted and glued.

dscn0323 (2).jpg

Progress is being made on this Marathon build.

Anybody remember the Marathon but I guess that is another Topic.

smiley

Steve

EarlyBird15/07/2020 08:31:24
186 forum posts
146 photos

Peter

I read one of your posts where you cut a ventilation hole in front of the pilot, so I did the same even though I thought the reason being was to keep the pilots feet warm. Ahh so now I can stop searching for a pilot with feet.

I am feeling happy today can you tell? The medication must be working!

Steve

Graham Davies 315/07/2020 09:09:05
66 forum posts
39 photos

All looking good Steve, good to see you having fun!

Regarding cooling, Peter is quite right. Wind (and cooling draught is only wind, missus!) relies on a difference in pressure. To get a draught from the front of the model to the rear, the pressure must be higher in front than behind. To achieve this, you need a bigger outlet than inlet. Otherwise, not much happens, apart from drag.

It's also worth considering what happens to the moving air inside the model. It needs to go past the hot bits and the tendency is to take the shortest and easiest path. Creating what appears to be small gaps is beneficial, because to maintain constant pressure, if volume is decreased, velocity must increase (we know what happens when you put your thumb over the end of a hose). So don't be afraid to add baffles.

There are some great shots of really effective baffling on one of the Laser threads. I think it's Jon's Hurricane. Jon has baffled the engine very tightly, and he knows a huge amount about cooling!

I have done similar for my Tempest. The design has a massive chin scoop, that would have been useless for cooling! The exhaust area is much smaller, and the path to it was direct. Instead I am using the cutout behind the spinner and creating an air path around the battery and ESC to exit in front of the leading edge.

Physics lesson over, as you were...

G

EarlyBird15/07/2020 09:45:58
186 forum posts
146 photos

Thanks G

Yes it is all about having fun.

Physics lessons! I remember Bernoulli. At college my favorite subject was hydraulics laminar and turbulent flow come to mind.

How can that possibly have been fifty years ago.

I wasted forty eight years by starting RC only two years ago.

Steve

Peter Miller15/07/2020 10:58:29
avatar
11211 forum posts
1321 photos
10 articles

I find that I normally do two sides wedged between the nose ring and firewall or rear former of the cowl and go from there.

It is very much "cut ans try"

The model with the air outlet in the cockpit is The OHmen.

EarlyBird15/07/2020 12:12:39
186 forum posts
146 photos

My method is measure, measure again, cut try then start again. smiley

That way I get more practice.

Can I ask because there are some things I do not understand why OHmen and not Ohmen for one and what does IIRC mean?

Spell check says there is no H in omen hmmm I get it now.

Steve

Peter Miller15/07/2020 12:26:55
avatar
11211 forum posts
1321 photos
10 articles

Oh yes.WE all "cut and try",usually a few times!!

the "OHmen" is my lousy typing!

Yes,you got the "Ohm" part of it. Several non modellers and one or two modellers didn't get it.

I also once did a plan called the Ohmsick Angel"

I don't use IIRC but I think it means "If I ReCall" but I could be wrong there. May be I should use "ISTR" just to baffle a few!!!

(I seem to remember)

EarlyBird15/07/2020 13:15:08
186 forum posts
146 photos

Now I am more confused not to worry as flying is the only thing that matters.

Ventilation from front to back.

dscn0327.jpg

dscn0325.jpg

dscn0326 .jpg

Last part of cowl ready

dscn0324.jpg

and fitted

dscn0328.jpg

Waiting for glue to dry then shaping with my David Plane which works like a dream.

Steve

Peter Miller15/07/2020 13:30:02
avatar
11211 forum posts
1321 photos
10 articles

Don't worry. It will all work out in the end!!

I work very much on the TLAR system.

(That looks about right)

EarlyBird15/07/2020 13:41:17
186 forum posts
146 photos

OHman what have I started. I can not handle acronyms.

I thought IIRC was to radio control using II instead of 2 but the context did not fit all the time and why use Roman numerals.

I did work out LMS was local model shop unless I am wrong.

Steve

Peter Miller15/07/2020 14:01:19
avatar
11211 forum posts
1321 photos
10 articles

Yes.

And then we have "IMHO" In My Humble Opinion"

Bob Cotsford15/07/2020 14:36:15
avatar
8636 forum posts
483 photos

iirc - If I Recall Correctly thumbs up

Nothing more satisfying than taking a razor plane to an unsightly lump of balsa and ending up with a streamlined, elegant shape. Oh yes, and a binfull or two of shavings!

EarlyBird15/07/2020 15:02:51
186 forum posts
146 photos

Well I have 'an unsightly lump of balsa'

dscn0329.jpg

from the back it looks good

dscn0330.jpg

but Bob from the front your description fits.

Peter your new system works a treat thank you.

Steve

EarlyBird16/07/2020 10:34:05
186 forum posts
146 photos

Carving the cowl.

I have started by using a stanley knife to take off the corners and shape close to the front nose ring and back plate.

dscn0331.jpg

The next stage is to use a Razor Plane.

Steve

EarlyBird16/07/2020 11:34:35
186 forum posts
146 photos

Razor plane done.

001.jpg

002.jpg

Ready for sanding to the fuselage using masking tape to protect areas that do not need sanding at this stage.

Steve

EarlyBird16/07/2020 20:14:19
186 forum posts
146 photos
Posted by Bob Cotsford on 15/07/2020 14:36:15:

iirc - If I Recall Correctly thumbs up

Nothing more satisfying than taking a razor plane to an unsightly lump of balsa and ending up with a streamlined, elegant shape. Oh yes, and a bin full or two of shavings!

I see what you mean definitely satisfying even though it is hardly a bin full of shavings. Just a bin and some shavings.

dscn0334.jpg

Next stage was to sand so I went outside in the warm sun and found it very pleasant, a warm glow inside as well as on the outside plus some free Vitamin D.

dscn0335.jpg

More work to do of course. I will pinch in the cheeks below the spinner and turn the vent slot into a smile. I like happy planessmiley

Steve

All Topics | Latest Posts

Please login to post a reply.

Support Our Partners
electricwingman 2017
Slec
CML
Sussex Model Centre
Advertise With Us
Sarik
Latest "For Sale" Ads
Has home isolation prompted you to start trad' building?
Q: The effects of Coronavirus

 Yes - for the first time
 Yes - but Ive bashed balsa before
 No - Ive existing projects on the bench
 No - Im strictly an ARTF person

Latest Reviews
Digital Back Issues

RCM&E Digital Back Issues

Contact us

Contact us

Magazine Locator

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

Find RCM&E!