SMALL - espritmodel.com SMALL - Telemetry SMALL - Radio
Reply
Thread Tools
Old Oct 29, 2012, 03:57 PM
I'm Addicted Already
Charlotte, NC
Joined Feb 2011
1,912 Posts
I don't think it matters if it is gas or electric, but rather the RPMs. I don't know what the rpms of the gasser that is causing problems, but may be something to think about. Man, there really are not a whole lot of 4 bladed props to choose from are there?
Another thing to consider, my motor is rated for 1960 watts with a 2 blade 15x8. i have been told that if I go to a 4 blade, to keep the same output, I need to go to a 13x8! Seems small to me.
NCRealEstateGuy is offline Find More Posts by NCRealEstateGuy
Reply With Quote
Sign up now
to remove ads between posts
Old Oct 29, 2012, 06:34 PM
Registered User
V2rider's Avatar
USA, MD, Hagerstown
Joined Jun 2009
3,349 Posts
Or, with that high of a kv you may be able to drop to a 5s pack and still run the 4 blade apc. I run that prop on my H9-40 size mustang on 5s and a P-60. Has good speed, and tons of thrust. I think a 5000ma 5s will be easier to fit in the hatch too.
V2rider is online now Find More Posts by V2rider
Reply With Quote
Old Oct 29, 2012, 07:14 PM
I'm Addicted Already
Charlotte, NC
Joined Feb 2011
1,912 Posts
V2, how much does your mustang weigh? I really do not know what the KV means... maybe I should have gotten the 350KV.
I am starting to think I may just go with a two blader.
NCRealEstateGuy is offline Find More Posts by NCRealEstateGuy
Reply With Quote
Old Oct 29, 2012, 09:07 PM
Registered User
V2rider's Avatar
USA, MD, Hagerstown
Joined Jun 2009
3,349 Posts
The Mustang weighs in at 7lb 10oz. A bit less than the P-47 will end up. I'm kind of hooked on this combo for the plane at the moment. Not quite as fast as the 15x10 2 blade was on 6s but, has better verticle, and a great sound.
I think you may have to high of a kv motor for this prop though. I played with some figures on ecalc till I got the current they listed for the 15x8 on 6s. When I drop it to 5s and swap to the 4 blade it says it will be pulling about 120 amps. Dropping to 4s puts it at 90 amps, pitch speed of 65mph and thrust at 203 oz. That might work, but these are all theory based on guesswork for the motor specs. Could be worth putting on a wattmeter and checking rpms though.
V2rider is online now Find More Posts by V2rider
Last edited by V2rider; Oct 31, 2012 at 10:54 AM. Reason: ...
Reply With Quote
Old Oct 30, 2012, 10:40 AM
Limey Jeff
Jeff Glasser's Avatar
Glastonbury, Somerset. U.K.
Joined Mar 2009
347 Posts
Oh Gree, that was fabulous!!!! yeah clever, and so subtle! but I think it's too understated. It's not so much weathered as flogged!!!

That's what happens when you get a new airbrush for Xmas!!

Jeff
Jeff Glasser is offline Find More Posts by Jeff Glasser
Reply With Quote
Old Oct 30, 2012, 10:42 AM
Limey Jeff
Jeff Glasser's Avatar
Glastonbury, Somerset. U.K.
Joined Mar 2009
347 Posts
Quote:
Originally Posted by Gree View Post
Thanks for the prop warning. However I will be using 6S electric so I think it will be fine.

Jeff don't worry I am going for something subtle and understated in the weathering department - like this example from RCscalebuilder.com...


Oh Gree, that was fabulous!!!! yeah clever, and so subtle! but I think it's too understated. It's not so much weathered as flogged!!!

That's what happens when you get a new airbrush for Xmas!!

Jeff
Jeff Glasser is offline Find More Posts by Jeff Glasser
Reply With Quote
Old Oct 31, 2012, 04:34 AM
Registered User
Gree's Avatar
Sydney, Australia
Joined Jun 2006
2,946 Posts
Wow Jeff you loved my subtle humour so much you said it twice.
Gree is offline Find More Posts by Gree
Reply With Quote
Old Oct 31, 2012, 05:16 AM
Registered User
Gree's Avatar
Sydney, Australia
Joined Jun 2006
2,946 Posts
Bit of a lesson learned halfway through the clear coating of the fuse...

If I put the clear on reeealllly light mist, it works fine. It I get a bit heavier it temporarily melts the silver paint, making all the really nice metal looking depth and scratches disappear, leaving a more uniform murky dull grey... So the fuse won't look as good as it did before the clear coating! Well half of it won't anyway

Oh well, Some bits will look ok, just not as metal-like. Like I said, practice plane...
Gree is offline Find More Posts by Gree
Last edited by Gree; Oct 31, 2012 at 06:57 AM.
Reply With Quote
Old Oct 31, 2012, 09:42 AM
swede
denial15's Avatar
United States, UT, Vineyard
Joined Aug 2005
3,865 Posts
.
denial15 is offline Find More Posts by denial15
Reply With Quote
Old Oct 31, 2012, 10:18 AM
I'm Addicted Already
Charlotte, NC
Joined Feb 2011
1,912 Posts
Sorry to hear that. My experience with any aluminum, chrome or silver paint is that it is a different beast. I have never used it in this hobby though.
I bet no one will notice except you.
Send us some pics and we will tell you if we see it or if it is just you.
NCRealEstateGuy is offline Find More Posts by NCRealEstateGuy
Reply With Quote
Old Oct 31, 2012, 11:39 AM
Scale Builder
United States, AZ, Litchfield Park
Joined Jul 2002
2,540 Posts
Why the clear coat on an electric bird Gree? I know this information comes too late but it has been my experience that anytime you clear coat over aluminum it ends up looking like silver paint. This has been true in the case of chrome and aluminum colored paints as well as the simulated aluminum finishes such as Rub-n-Buff and Skini-Dip. Even putting clear coat over real aluminum can have the same effect. This is why I prefer camouflage! And because overall silver airplanes are REALLY tough to keep oriented in flight for my aging eyeballs. Whatever issues you're having Gree the Jug looks fantastic and I'm sure the finished airplane is going to be a head turner.
Chad Veich is online now Find More Posts by Chad Veich
Reply With Quote
Old Oct 31, 2012, 05:03 PM
Registered User
Gree's Avatar
Sydney, Australia
Joined Jun 2006
2,946 Posts
Hi Chad. The clear is necessary only because when I buff up the paint to get a more realistic look, it takes the top surface off, and leaves the paint kind of 'un-set'. When I started painting the star and bar on my wing, the masking film lifted off the paint. Also my rub on transfers don't stick very well to it.


Oh and it is very noticeable. Like Chad says a lot just turned into silver paint. The fuse was beautiful before. Really looked like metal. I debated hard about leaving it, and just hand brushing some clear where the stencils needed to go so they would stick. But in the end I did the deed. Wrong decision obviously....

I am going to paint the anti glare strip today so will post some shots then...


Practice plane, practice plane, practice plane!
Gree is offline Find More Posts by Gree
Reply With Quote
Old Oct 31, 2012, 05:19 PM
Rangers Lead the Way
Joined Mar 2010
2,121 Posts
Quote:
Originally Posted by NCRealEstateGuy View Post
I don't think it matters if it is gas or electric, but rather the RPMs. I don't know what the rpms of the gasser that is causing problems, but may be something to think about. Man, there really are not a whole lot of 4 bladed props to choose from are there?
RPMs are definitely the issue for the gassers. These little motors (and 2-strokes of any size) have a very narrow operating range outside of which bad things start to happen, and they have no torque to speak of. Go too hot or too fast and they fail. Too slow or too rich and you break reed valves and foul plugs.

Electrics are totally different and much more flexible. There is actually good prop selection if you know where to look - but it will cost you. There is Biela and Varioprop - nice but super pricey. At the more reasonable end, Zinger (google zingerpropellor) will fab you up a multiblade prop (3,4,5) from any of their wood tractor series. So there is plenty of choice, but you have to pay. You just have to run the numbers on propcalc to see what the optimum mix of cell count, motor, and prop gets you to a reasonable solution.

It generally helps to have a motor like the Scorpions, or the Neu / Hacker inrunners that can take a lot of amps, if you are looking for a solution that allows the same motor to fly 2-blade or multiblade at your option. I choose my motors very carefully with that objective in mind. Example for a 10.5-11.5lb .60-.120 Sea Fury and it's 5-blade scale prop:

The optimal motor here is a Hacker B50 9XL or 10XL or the Neu 1515/1 or -21/1, both running a 6.7 gearbox. Either motor can run at 90A and both support high cell counts, up to 10S or even more. As a result, I can run a 16x16 APC pattern prop on the higher cell count if I want speed (lots of speed ), or I could run a Zinger 5-blade prop made of their 16x14 or even the 18x16 cut down to 16.

The 2-blade prop will deliver 120mph pitch speed and 25lb thrust (not all of it delivered static since the prop will stall, but actually a desirable result in terms of reducing p-factor) at 78A. The 5-blade 16x16 will deliver 91mph pitch speed at the same 25lb thrust, at 94A, on 8S. Because both props deliver a ton of thrust relative to the model weight, they will both come close to achieving speeds in the air that are pretty close to the pitch speed and both will have excellent vertical performance. And even with the penalty in performance, the 5-blade will still deliver more than adequate scale speeds.

The key here is the motor's ability to withstand amps and not being shy about running big pitches. So many times I see people running 16x10s or something like that - lots of performance left on the table. What would not work in this example is the equivalent power (on paper) Eflite 110 or similar traditional outrunner, because it is not rated for more than 60-65A peak (15sec).
TTRotary is online now Find More Posts by TTRotary
Reply With Quote
Old Oct 31, 2012, 10:09 PM
Registered User
Gree's Avatar
Sydney, Australia
Joined Jun 2006
2,946 Posts
Masking

Anti Glare Strip and Tail Identification Stripes
Well moving on from my unfortunate incident with the aluminium paint, I masked up the anti glare strip and the tail identification stripes. Looking at several photos and drawings of these tail stripes, there seemed to be a fair amount of variation in width. I settled for what I considered the average width and made all the stripes 40mm wide.

Despite making the surface look less like metal (it isn't too awful, but it looks about 40% as good as it did before), the clear satin paint solved the issue I was having with the paint coming off on the masking tape. So this at least is a big plus.

I managed to put a coat of paint on the tail control surfaces, but didn't get time to do the fuse today. I also just rubbed the black back with my 0000 steel wool. Looks a lot lighter in tone and I have a worn look with some rivets and raised edges worn away to the metal. I didn't overdo this. Photos of this later when I get the whole fuse done.



Oh by the way NCRealEstateGuy (man you have to get a shorter handle!) I found this PDF file for prop selection. Maybe you might find it useful...
Gree is offline Find More Posts by Gree
Reply With Quote
Old Nov 01, 2012, 01:07 AM
Registered User
Gree's Avatar
Sydney, Australia
Joined Jun 2006
2,946 Posts
Flat Black Bits Done
Well I couldn't resist and snuck down to the garage to finish painting the fuse with flat black in the places I had masked. I am going to pay dearly later for this misuse of my time!

After it dried I scrubbed it with steel wool to wear the newness off. I am relatively happy with how it came out. When I start weathering more with the airbrush I'll lighten the black even more.

I just had to temporarily mount the previously completed cowl, and sit the canopy on to see where I am headed. A little motivational ploy. Who knows, we might actually be getting somewhere after 4 plus years!




Next, stars and bars, invasion stripes and stencils!
Gree is offline Find More Posts by Gree
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Question motor battery prop combination for top flite P47 63"? Gree Glow to Electric Conversions 27 Jul 20, 2014 08:42 PM
Discussion Yes another top flite giant P47 build pand9 Fuel Warbirds 5 Jan 07, 2009 06:25 AM
Discussion P47 Top Flite - Making Off rushspbr Fuel Warbirds 18 Dec 07, 2006 09:03 PM
For Sale Top Flite P47 Tom Jennings Aircraft - Fuel - Airplanes (FS/W) 7 Jan 16, 2006 11:51 AM
Top Flite DC-3 Eddie P Scale Kit/Scratch Built 10 Jul 20, 2001 06:11 PM