Thread Tools
Old Jan 28, 2002, 04:17 PM
Van is offline
Van
Find More Posts by Van
Van
Registered User
Van's Avatar

Motor calculations for Grumman Albatross


Can someone explain static thrust and inflight thrust to me? I was putting some numbers into P-calc, seeing how increasing gearing reduces amp draw, and I noticed static thrust went up as I increased the pitch (I expected that) but inflight thrust went down.

Here's what I put in:

motor: Speed 400
Prop:....................7x3........7x5........7x6
Gearing:................1:1........2:1........2:1
Amp draw:............16.3.......9.9.......10.7
RPM of prop:.........9810......8274.....7863
Static thrust oz:....12.4.......14.7......15.9
Inflight thrust:.......14.3.......10.2.......9.2
Pitchspeed mph:....27.9.......39.2......44.7

Here's why I'm curious. I ordered a Grumman Albatross from Hobby Lobby (last sale) and I was thinking about using gearboxes to reduce the amp draw for longer flight times. I also read some treads about people having problems taking off from water. Would increasing the static thrust help that?
Sign up now
to remove ads between posts
Old May 17, 2007, 04:19 AM
twinstarchris is offline
Find More Posts by twinstarchris
Electric forever,
twinstarchris's Avatar
Interesting stuff.
I'm gona get a flying boat as I can use a nearby lake. I'm looking to use my old Twinstar stuff so Im looking a the "albatross" or an "Aventura III"
I notice this is an old post. What did you settle on in the end and how do you think it compares to the aventura III?

http://www.rcuniverse.com/magazine/a...TOKEN=86430768
Old Apr 22, 2009, 06:14 PM
Brian Milsom is offline
Find More Posts by Brian Milsom
Registered User

Static vs. Inflight thrust


Hi Van,
Static thrust is the thrust measured with motor and propellor mounted in a fixed position such as a test stand. In flight thrust is the measured thrust when the motor and propellor are actually in forward motion. A propellor is far more efficient when it is moving forward than it is when it is stationary. Hope this answers your question. Brian Milsom
Quote:
Originally Posted by Van
Can someone explain static thrust and inflight thrust to me? I was putting some numbers into P-calc, seeing how increasing gearing reduces amp draw, and I noticed static thrust went up as I increased the pitch (I expected that) but inflight thrust went down.

Here's what I put in:

motor: Speed 400
Prop:....................7x3........7x5........7x6
Gearing:................1:1........2:1........2:1
Amp draw:............16.3.......9.9.......10.7
RPM of prop:.........9810......8274.....7863
Static thrust oz:....12.4.......14.7......15.9
Inflight thrust:.......14.3.......10.2.......9.2
Pitchspeed mph:....27.9.......39.2......44.7

Here's why I'm curious. I ordered a Grumman Albatross from Hobby Lobby (last sale) and I was thinking about using gearboxes to reduce the amp draw for longer flight times. I also read some treads about people having problems taking off from water. Would increasing the static thrust help that?


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Source for Grumman Albatross, PB-Y Catalina & COOT A donjiskra Waterplanes 4 Dec 22, 2004 05:59 PM
Plans for a Grumman albatross or widgeon rcminiman Scale Kit/Scratch Built 10 Dec 08, 2004 03:20 AM
Which fan/motor combo for K&A L39 Albatross? DeanW Electric Ducted Fan Jet Talk 9 Feb 01, 2002 10:26 AM
Paint for Grumman Albatross? Jedd Scale Kit/Scratch Built 11 May 30, 2001 11:53 PM
Motor Combo for Balsacraft EasyStreet dav75 Electric Plane Talk 4 Apr 22, 2001 05:58 PM