Espritmodel.com Telemetry Radio
Reply
Thread Tools
Old Jan 24, 2013, 06:20 PM
Registered User
Joined Dec 2005
5,408 Posts
Jon,

Where is the CoG on the plane? Perhaps leaving the top wing solid instead of 'holey' would help with keeping some weight forward?

I thnk it would be better to stay with the original tail setup and add weight to the nose. Some planes and some designes just seem to require that to happen. Cutting, skimping or changing a design just to avoid a few grams is not always wise.
Obake is offline Find More Posts by Obake
Reply With Quote
Sign up now
to remove ads between posts
Old Jan 25, 2013, 01:22 AM
UAS Pilot/Tech Instructor
CryHavoc's Avatar
United States, CA, San Diego
Joined Apr 2000
1,422 Posts
As this is the prototype, now is the time to make changes so I think lightening the tail is on the right track. Besides, anything you can do to lighten and reduce drag on a bipe is only a positive, especially at the small margins of error for a micro.

And..... the thinner tail surfaces just look right to boot.

Mike
CryHavoc is online now Find More Posts by CryHavoc
Reply With Quote
Old Jan 25, 2013, 02:45 AM
Microaces Wingman
deadbird's Avatar
UK. Dorset
Joined Jun 2009
375 Posts
Quote:
Originally Posted by Obake View Post
Jon,

Where is the CoG on the plane? Perhaps leaving the top wing solid instead of 'holey' would help with keeping some weight forward?

I thnk it would be better to stay with the original tail setup and add weight to the nose. Some planes and some designes just seem to require that to happen. Cutting, skimping or changing a design just to avoid a few grams is not always wise.
The COG is slightly forward of half way on the upper wing. Because of the aesthetic improvement on the tail I'm going to try it out first to see how she behaves in the air. We always have the fall back position.

I can't think it would cause any major problems but you never know unless you prototype! It also makes the build a little different and more interesting too I think. Hmmmmm - we'll have to see. Maybe a test flight this weekend.
deadbird is offline Find More Posts by deadbird
Reply With Quote
Old Jan 25, 2013, 04:36 AM
Registered User
Gulf Breeze, FL
Joined Jul 2006
2,823 Posts
Deleted
speedy01 is online now Find More Posts by speedy01
Last edited by speedy01; Jan 26, 2013 at 07:13 AM.
Reply With Quote
Old Jan 25, 2013, 05:23 AM
Registered User
Gulf Breeze, FL
Joined Jul 2006
2,823 Posts
Quote:
Originally Posted by deadbird View Post
The COG is slightly forward of half way on the upper wing.
Now there's an interesting, often discussed subject - determining the Center of Gravity for biplanes! RCGroups details everything from using the "shadow method" to using the attached. Those discussions often include settings for the incidence of top and bottom wings (decalage), as well as for the horizontal stab ... which leads to Center of Gravity versus Center of Lift discussions .. which leads to dihedral discussions, etc, etc.

My friend Pete (mtflyr) who can make anything fly, including his many small WWI bipes, uses the following scientific method: tosses the model onto his well padded bed, adjusting components (mainly battery) until he gets a good glide. Further adjustments are made after flying.

What method are you using, Jon?

Gene K
speedy01 is online now Find More Posts by speedy01
Reply With Quote
Old Jan 25, 2013, 08:30 AM
Microaces Wingman
deadbird's Avatar
UK. Dorset
Joined Jun 2009
375 Posts
I'm using the 'SAS' method Gene - Suck it And See!

Not having designed a biplane before I went off around the threads & looked at various CoG methods. I established from this that it should be somewhere slightly forward of the centre of the upper wing chord.

On the first build it turned out that the balance point was slightly behind the centre of the chord so I was prepared for a tail heavy aircraft on the maiden.

The first flight confirmed this as it took off after about a foot of runway. After wrestling it down gently I then start adding ballast until it flew right.

Because these aircraft are fairly tough I'm not too concerned about 'hard landings' due to instability so it give me every opportunity to employ the SAS method!

Jon
deadbird is offline Find More Posts by deadbird
Reply With Quote
Old Jan 25, 2013, 08:52 AM
Registered User
Gulf Breeze, FL
Joined Jul 2006
2,823 Posts
Quote:
Originally Posted by deadbird View Post
... the 'SAS' method - Suck it And See!
Must be an English expression.

Gene K
speedy01 is online now Find More Posts by speedy01
Reply With Quote
Old Jan 25, 2013, 08:58 AM
Microaces Wingman
deadbird's Avatar
UK. Dorset
Joined Jun 2009
375 Posts
One of those phrases you grow up with, but nobody else knows what the hell you're going on about.

It made it into the Cambridge on-line dictionary though
deadbird is offline Find More Posts by deadbird
Reply With Quote
Old Jan 25, 2013, 06:21 PM
Registered User
Joined Dec 2005
5,408 Posts
...
Obake is offline Find More Posts by Obake
Last edited by Obake; Jan 26, 2013 at 11:01 AM.
Reply With Quote
Old Jan 25, 2013, 07:17 PM
Registered User
Gulf Breeze, FL
Joined Jul 2006
2,823 Posts
Quote:
Originally Posted by Obake View Post
I shall endeavour to never post again in this thread.
No, please continue to contribute. The expression of my opinions was over the top, and I apologize.

Gene K
speedy01 is online now Find More Posts by speedy01
Reply With Quote
Old Jan 26, 2013, 01:50 PM
Microaces Wingman
deadbird's Avatar
UK. Dorset
Joined Jun 2009
375 Posts
Well I'm not going to be doing any test flying this weekend on the Hawk as the wind has whipped up and we are forecast gales tomorrow.

I've also had a bit of an artistic block with the fuselage illustration. Stupid really but its a case of loosing the knack of it temporarily. Usually a good indicator that I'm knackered! Need to take a day off and go blow the cobwebs away I think.
deadbird is offline Find More Posts by deadbird
Reply With Quote
Old Jan 31, 2013, 03:04 PM
MICROACES's Avatar
Joined Sep 2012
382 Posts
400mAh 1s 30C Lipo samples arrived this week.

They are a good fit in the larger cavity of the P-6E and will mean, if used, the majority of the additional ballast in the nose can go and the flight times should be as leisurely as the aircraft is to fly.

All I have to do now is wait for the wind to die down.
MICROACES is offline Find More Posts by MICROACES
Site Sponsor
Old Jan 31, 2013, 04:17 PM
OY-5542
Chrizz's Avatar
Denmark, Central Denmark Region, Silkeborg
Joined Nov 2009
722 Posts
Hmmm! Looks good! ...All I need now is a budget... of any kind :-)
Chrizz is offline Find More Posts by Chrizz
RCG Plus Member
Latest blog entry: Oxy 0.5
Reply With Quote
Old Feb 03, 2013, 02:32 PM
Registered User
Joined Nov 2012
11 Posts
Aircraft Markings and Pilot

Change of subject back to the topic of aircraft markings and pilots. Here's what the US Air Force Museum website says about the aircraft they have on display:

The only original P-6E still in existence, this P-6E appears in the colors and markings of the airplane assigned to Capt. Ross G. Hoyt, Commanding Officer of the 17th Pursuit Squadron, 1st Pursuit Group, based at Selfridge Field, Mich. in 1933. Edward S. Perkins of Anniston, Ala., donated it to the museum, and the Department of Aviation Technology at Purdue University restored it in 1963.

And here's a link to this info:

http://www.nationalmuseum.af.mil/fac...eet.asp?id=337

Finally, here's a link to my favorite photo of the P-6E in flight:

http://www.nationalmuseum.af.mil/sha...-1234P-022.jpg

Enjoy!

--Hatman
Hatman is offline Find More Posts by Hatman
Reply With Quote
Old Feb 07, 2013, 02:52 PM
MICROACES's Avatar
Joined Sep 2012
382 Posts
Quote:
Originally Posted by Hatman View Post
Change of subject back to the topic of aircraft markings and pilots. Here's what the US Air Force Museum website says about the aircraft they have on display:

The only original P-6E still in existence, this P-6E appears in the colors and markings of the airplane assigned to Capt. Ross G. Hoyt, Commanding Officer of the 17th Pursuit Squadron, 1st Pursuit Group, based at Selfridge Field, Mich. in 1933. Edward S. Perkins of Anniston, Ala., donated it to the museum, and the Department of Aviation Technology at Purdue University restored it in 1963.

And here's a link to this info:

http://www.nationalmuseum.af.mil/fac...eet.asp?id=337

Finally, here's a link to my favorite photo of the P-6E in flight:

http://www.nationalmuseum.af.mil/sha...-1234P-022.jpg

Enjoy!

--Hatman
I think Captain Hoyt will have to grace the Hawk with his presence in the cockpit. He certainly cuts a dash with his fine facial whiskers! Thank you for the further research Hatman.

I have finally managed to find some time & inspiration to continue the fuselage illustration. It is proving to be a really slow render but the detail is so wonderful, what with zip fastners, buckles and even a combination lock. The illustration below still needs a lot of work in the light & shade department.

Jon
MICROACES is offline Find More Posts by MICROACES
Site Sponsor
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
For Sale Royal Curtiss P-6E (Hawk) Kit rcrube Aircraft - Fuel - Airplanes (FS/W) 0 Sep 30, 2012 05:49 PM
For Sale Royal Curtiss P-6e Hawk Plans ama-hobby Aircraft - Fuel - Airplanes (FS/W) 0 Mar 21, 2006 06:45 PM
For Sale Royal Curtiss P-6e Hawk Plans ama-hobby Aircraft - Fuel - Airplanes (FS/W) 0 Feb 21, 2006 06:40 AM
Curtiss P-6E Hawk plans needed sgtdirt Free Flight 6 May 20, 2005 05:38 AM
Curtiss P-6E Hawk Gordon Scale Kit/Scratch Built 8 Dec 10, 2002 09:13 AM