CROW on Large Skymaster Viperjet??
08-18-2010, 08:41 AM
#1
CROW on Large Skymaster Viperjet??
Hi All,
Am maidening my Large Skymaster Viper this weekend, and am a bit nervous since we fly at 6300 feet and with the summer heat and the high altitude, the air is thin and planes DONT LIKE TO SLOW DOWN on our 625 foot runway. [sm=idea.gif]
DOES ANYBODY USE CROW??? IF YES, COULD YOU EXPLAIN HOW MUCH, AND WHEN YOU SET IT ON APPROACH????
Thanks in advamce guys!
Shaz
Am maidening my Large Skymaster Viper this weekend, and am a bit nervous since we fly at 6300 feet and with the summer heat and the high altitude, the air is thin and planes DONT LIKE TO SLOW DOWN on our 625 foot runway. [sm=idea.gif]
DOES ANYBODY USE CROW??? IF YES, COULD YOU EXPLAIN HOW MUCH, AND WHEN YOU SET IT ON APPROACH????
Thanks in advamce guys!
Shaz
08-18-2010, 09:58 AM
#2
My Feedback: (39)
Join Date: Oct 2002
Location: Salinas,
CA
Posts: 122
Likes: 0
Received 0 Likes
on
0 Posts
RE: CROW on Large Skymaster Viperjet??
I had it on my KingCat, it did help with the wing rocking but I,m not a fan of killing lift (crow). I will be starting on a Viper Jet soon and plan on using drag devices (flaps, speed brakes), no crow.
Steve
Steve
08-18-2010, 10:30 AM
#3
Junior Member
Join Date: Oct 2003
Location: Orleans, ON, CANADA
Posts: 17
Likes: 0
Received 0 Likes
on
0 Posts
RE: CROW on Large Skymaster Viperjet??
Crow is a great way to bring a sailplane down without having it speed up - by lifting the ailerons and dropping the flaps. The result is a nose down attitude that can be corrected for at the last second to grease the landing, or maintained if the objective is to dork the plane on the landing spot. Either way, the operative phrase is - nose down attitude - and the model is a low-wing-loading, high-aspect-ratio sailplane that is capable of flying very slowly.
While I am sure the same control throws will work on a jet, I doubt very much that you want to adopt the required nose down attitude.
If you want to slow your jet down, drop the flaps and raise the ailerons a smidgen.
Good luck.
While I am sure the same control throws will work on a jet, I doubt very much that you want to adopt the required nose down attitude.
If you want to slow your jet down, drop the flaps and raise the ailerons a smidgen.
Good luck.
08-18-2010, 10:35 AM
#4
RE: CROW on Large Skymaster Viperjet??
Hey Guys,
I think I may been misleading in my question. I am aware of the principles of CROW and have used it on my Boomerang XL very effectively by lowering flaps to max setting and raising both ailerons about 1".
What I am asking is are there Skymaster Viperjet owners flying their jets currently who use this function and if yes , what are the degrees/angles/centimeters/inches of deflection they are using on flaps and ailerons to effectively slow down their jets on final?
Thanks again everyone!
Shaz
I think I may been misleading in my question. I am aware of the principles of CROW and have used it on my Boomerang XL very effectively by lowering flaps to max setting and raising both ailerons about 1".
What I am asking is are there Skymaster Viperjet owners flying their jets currently who use this function and if yes , what are the degrees/angles/centimeters/inches of deflection they are using on flaps and ailerons to effectively slow down their jets on final?
Thanks again everyone!
Shaz
08-18-2010, 11:23 AM
#5
My Feedback: (49)
Join Date: Jul 2002
Location: Arlington, TX
Posts: 1,040
Likes: 0
Received 0 Likes
on
0 Posts
RE: CROW on Large Skymaster Viperjet??
My buddy has a large SM Viper Jet and we use no crow. The airplane will fly quite slow without crow. It will however drop a wing when stalled (like most higher performance aircraft do). If you feel the need to by all means program a reasonable amount of crow, I sure wouldnt start off with the amount you used on your Boomerang, not for the first flights anyway.
Something that I was taught to do that most guys dont do or are afraid to do with a new model on the first flight is to take it up to a safe altitude and do some intentional stalls with and with out flaps so as to learn the stall characteristics of a new airplane.
Something that I was taught to do that most guys dont do or are afraid to do with a new model on the first flight is to take it up to a safe altitude and do some intentional stalls with and with out flaps so as to learn the stall characteristics of a new airplane.
08-18-2010, 12:51 PM
#7
RE: CROW on Large Skymaster Viperjet??
Shaz:
The Viper is a floater and can be landed at an incredible low speed. Just take a look at this landing to get an idea. http://www.youtube.com/watch?v=-OgX8...os=RfvFmTr4kik
The Viper is a floater and can be landed at an incredible low speed. Just take a look at this landing to get an idea. http://www.youtube.com/watch?v=-OgX8...os=RfvFmTr4kik
08-18-2010, 01:28 PM
#8
Senior Member
Join Date: Mar 2003
Location: Uetliburg, SWITZERLAND
Posts: 397
Likes: 0
Received 0 Likes
on
0 Posts
RE: CROW on Large Skymaster Viperjet??
I use crow on my VJ since one Year with great succes.
But I modified also flaps to slotted flaps, like you see on pics below.
This configuration makes possible steep decendings without increase the speed.
My settings: during extend flaps to full both ailerons raising up 10 mm. elvator 2 mm up.
Regards
Fritz/Switzerland
But I modified also flaps to slotted flaps, like you see on pics below.
This configuration makes possible steep decendings without increase the speed.
My settings: during extend flaps to full both ailerons raising up 10 mm. elvator 2 mm up.
Regards
Fritz/Switzerland
08-18-2010, 08:55 PM
#9
RE: CROW on Large Skymaster Viperjet??
This is the amount I had on mine, can't remember how much it was, but it was noticable in the handling, I also had a bit of down elevator mixed in.
Few departure pics just for you Kevin! 
08-19-2010, 10:08 AM
#16
RE: CROW on Large Skymaster Viperjet??
They don't need crow to slow for landing. With full flaps the decent rate is really nice.
Just don't get the Viper too slow in crosswind landings. It will drop a wing HARD in the opposite direction of the bank. Just don't ask me how I know. [
]
PaulD
Just don't get the Viper too slow in crosswind landings. It will drop a wing HARD in the opposite direction of the bank. Just don't ask me how I know. [
]PaulD
08-19-2010, 10:45 AM
#17
My Feedback: (49)
Join Date: Jul 2002
Location: Arlington, TX
Posts: 1,040
Likes: 0
Received 0 Likes
on
0 Posts
RE: CROW on Large Skymaster Viperjet??
The purpose for crow on takeoff is the same as it is for landing. The raising of both ailerons is a way to effectivly put temporary "washout" in the wing. This in effect means that the outter part of each wing panel is flying at a reduced angle of attach relative to the inner part of the wing which is intended to keep the tips flying at a point where the root or inner part of the wing is stalled (at or beyond the "critical angle of attach").
Therefore is you were to get airbone at a slower speed or a higher angle of attach than on a "normal" takeoff the margin for error is reduced due to less chance of tip stalling at extremly low altitude.
Therefore is you were to get airbone at a slower speed or a higher angle of attach than on a "normal" takeoff the margin for error is reduced due to less chance of tip stalling at extremly low altitude.
