Pham (Username “Dalat” on RCGroups) emailed me with some information about his rubber powered ducted fan F104 featured on this page.
He said that at this Pistachio scale the F104G was a real challenge: The fan is less than 1” in diameter and the tiny wing area with negative dihedral spans just 6 inches.
“I was very surprised that the FAI TAN Rubber can drive the fan to 12,000 rpm!!”
Theoretically it could stay 3 times longer in the air as in the video (which is 8 secs). The performance and efficiency of this configuration is really poor - about 10 times less than other conventional Pistachio scale models. Despite his achievement, Pham claims to be no expert in rubber power and relies on basic formulae to compute the maximum turns for any given motor.
The rubber used on this F104 was thin: FAI TAN 5/1999 (apparently regarded as a very high performance batch) cut to size 0.64 gr/meter, and forming a Loop 50 cm Long, weighing 0.64 gr. Theoretically the absolute max turns should be 5000 turns. On the video the F104 was just wound to 1800 turns and did 8 secs.
On a later test with 3600 turns it did 16 secs, but no one was there to record the flight…”More turns I dared not inside this fuse!”
Pham sent a link to another video showing his semi scale Skystreak D 558-1 test with the same 1 inch ducted fan. “This one is easy to trim and was only wound to 60 % of max turns...for the same reason.”
He said that at this Pistachio scale the F104G was a real challenge: The fan is less than 1” in diameter and the tiny wing area with negative dihedral spans just 6 inches.
“I was very surprised that the FAI TAN Rubber can drive the fan to 12,000 rpm!!”
Theoretically it could stay 3 times longer in the air as in the video (which is 8 secs). The performance and efficiency of this configuration is really poor - about 10 times less than other conventional Pistachio scale models. Despite his achievement, Pham claims to be no expert in rubber power and relies on basic formulae to compute the maximum turns for any given motor.
The rubber used on this F104 was thin: FAI TAN 5/1999 (apparently regarded as a very high performance batch) cut to size 0.64 gr/meter, and forming a Loop 50 cm Long, weighing 0.64 gr. Theoretically the absolute max turns should be 5000 turns. On the video the F104 was just wound to 1800 turns and did 8 secs.
On a later test with 3600 turns it did 16 secs, but no one was there to record the flight…”More turns I dared not inside this fuse!”
Pham sent a link to another video showing his semi scale Skystreak D 558-1 test with the same 1 inch ducted fan. “This one is easy to trim and was only wound to 60 % of max turns...for the same reason.”
Here's an interesting thread for the miniature engineering types.
An attempt to build a lighter servo. So far at 0.55g and working well.
http://www.rcgroups.com/forums/showthread.php?t=1897330
This video link shows it in action.
http://www.youtube.com/watch?feature=player_embedded&v=fE_Y6ogMKt4
An attempt to build a lighter servo. So far at 0.55g and working well.
http://www.rcgroups.com/forums/showthread.php?t=1897330
This video link shows it in action.
http://www.youtube.com/watch?feature=player_embedded&v=fE_Y6ogMKt4
This Italian modeller has built a working 0.5 g servo - NB not an actuator!
http://www.rcgroups.com/forums/showpost.php?p=26532143&postcount=50
http://www.rcgroups.com/forums/showpost.php?p=26532143&postcount=50
There's a nice thread on a well engineered Avro 504 depron kit that an enthusiast in the US produces here:
http://www.rcgroups.com/forums/showthread.php?t=1968033
http://www.rcgroups.com/forums/showthread.php?t=1968033
The amazing RC 3" span 10mm Ducted Fan by the German micro builder ChrisT is making progress.
UPDATE: It has now flown successfully!
http://www.rcgroups.com/forums/showthread.php?t=1606841
World's smallest RC ducted fan model?
This electric ducted fan model has a 3" wingspan. The modeller built everything from scratch including the 10mm dia. ducted fan and its motor plus the controller and actuator.
http://www.rcgroups.com/forums/showthread.php?t=1606841
http://www.rcgroups.com/forums/showthread.php?t=1606841
The fan unit is made using the Shapeways 3D printing process. That is a 10mm (!) dia ducted fan powered by a hand made single phase brushless "reversed" inrunner. The permanent magnet rotor rotates inside the stationary coil. The actuator below is also custom made.
A Microlight Vapor Indoor fitted with retracts!
Rubber powered Ducted Fan Mig15
This Japanese model is 20 years old - still flies perfectly!
http://www.youtube.com/watch?v=PSWVOkaLaPs&feature=player_detailpage
http://www.youtube.com/watch?v=PSWVOkaLaPs&feature=player_detailpage
Another Rubber powered Ducted Fan
And here's a scale F104 ducted fan.
http://www.rcgroups.com/forums/showpost.php?p=25626418&postcount=75
8 inches span and 1 inch diameter DF. Fan Speed about 10'000 rpm.
http://www.rcgroups.com/forums/showpost.php?p=25626418&postcount=75
8 inches span and 1 inch diameter DF. Fan Speed about 10'000 rpm.
A 2" wingspan Radio Controlled biplaneThere is a thread here devoted to Thumbkin, a biplane with a 2" wingspan that flies extremely well
http://www.rcgroups.com/forums/showpost.php?p=29201938&postcount=1 |
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