Engine losing power during loop.. Saito 91
08-01-2007, 02:05 PM
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RE: Engine losing power during loop.. Saito 91
ORIGINAL: 1THEPALMER
Get a bigger prop and quit trying to get high RPM. The engine delivers best power when loaded down with a big prop..
10000 RPM on the ground is too fast. I still think you are way too lean. OPEN THE HIGH SPEED NEEDLE AT LEAST 1/2 TURN!!!!!!!!!
Get a bigger prop and quit trying to get high RPM. The engine delivers best power when loaded down with a big prop..
10000 RPM on the ground is too fast. I still think you are way too lean. OPEN THE HIGH SPEED NEEDLE AT LEAST 1/2 TURN!!!!!!!!!
1THEPALMER.... Since the Saito 100 is swinging the 14 X 6 prop at 9900 rpm and that is on the rich side...what do you think would be the proper prop to try and what rpm do you think we should get with that prop? When I fly Friday I will increase the needle to several clicks rich for all test flights and then try to find the sweet spot for that combination...
08-01-2007, 04:54 PM
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RE: Engine losing power during loop.. Saito 91
Richard, I found that my Saito 100 would perform best loaded to about 9200 - 9300 static. It didn't go as well with a lighter prop like a 14 x 6 as it did with a 14 x 8.
Try an APC 14 x 8 and see how she goes. It should do 9200 - 9300 static or thereabouts.
The Saito .91 on the other hand seemed happier in the high nines unloading to early tens in the air. A 13 x 8 or 14 x 6 will work well on the Saito .91, both of which should do about 9800 rpm static.
Try an APC 14 x 8 and see how she goes. It should do 9200 - 9300 static or thereabouts.
The Saito .91 on the other hand seemed happier in the high nines unloading to early tens in the air. A 13 x 8 or 14 x 6 will work well on the Saito .91, both of which should do about 9800 rpm static.
08-01-2007, 05:00 PM
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RE: Engine losing power during loop.. Saito 91
[quote]ORIGINAL: Richard39
ORIGINAL: Ed Cregger
I wish I could be at your field while you are flying the model.
A Saito .91 should be able to pull a nine pound model through a loop with ease. I'm thinking that there may be a plumbing problem/tuning problem/etc., that is causing your problem. Conceivable, even a trim problem with the model.
My Bridi Deception of 1982 weighed 9.5 lbs., yes, it was heavy. It was my first fiberglass and K&B Superpoxy paint job model. Plus it was built from a kit with heavy wood. With that said, the OS .61 FSR with tuned pipe (tuned for the climb) would loop that model at half throttle. While I'm not sure that the Saito .91 was anywhere near as strong as the the piped OS .61 FSR, it sounds close enough that your model should be looping with ease, if everything is okay aerodynamically.
I have seen some set ups (incidence/etc.) that could make looping without a snap roll at the top really rough to accomplish.
I have both the Saito .91 and the 1.00 and love them both. I am a big Saito fan. They are kind of like a bulldog - they grow on you after a while.
Ed Cregger
Ed.... what incidence would cause the airplane to not loop and snap roll at the top... ?I found the airplane had 1.5 degrees of negative incidence in the wing but have corrected... The wing and the elevator now are at 0 degree incidence.
I wish I could be at your field while you are flying the model.
A Saito .91 should be able to pull a nine pound model through a loop with ease. I'm thinking that there may be a plumbing problem/tuning problem/etc., that is causing your problem. Conceivable, even a trim problem with the model.
My Bridi Deception of 1982 weighed 9.5 lbs., yes, it was heavy. It was my first fiberglass and K&B Superpoxy paint job model. Plus it was built from a kit with heavy wood. With that said, the OS .61 FSR with tuned pipe (tuned for the climb) would loop that model at half throttle. While I'm not sure that the Saito .91 was anywhere near as strong as the the piped OS .61 FSR, it sounds close enough that your model should be looping with ease, if everything is okay aerodynamically.
I have seen some set ups (incidence/etc.) that could make looping without a snap roll at the top really rough to accomplish.
I have both the Saito .91 and the 1.00 and love them both. I am a big Saito fan. They are kind of like a bulldog - they grow on you after a while.
Ed Cregger
Ed.... what incidence would cause the airplane to not loop and snap roll at the top... ?I found the airplane had 1.5 degrees of negative incidence in the wing but have corrected... The wing and the elevator now are at 0 degree incidence.
---------------------------
It truly depends on each and every model and its weight, how it is set up, wing area, etc. I would say that 1.5 degrees negative incidence wasn't helping the situation. <G>
Ed Cregger
08-02-2007, 08:45 PM
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RE: Engine losing power during loop.. Saito 91
Hi Richard: Larry has the numbers about right. I fly my 91 on a MOJO profile with a APC 15x4wide, Plane has 1000sqin of wing and comes in under 8 lbs. This combo will go straight up from hovering forever. The engine produces its max torque below 9000.
These engines do not really like to be reved high, but shine when loaded down. I think you are too focused on static RPM, If the plane is trying to rip it's self from your hands when held up @ full throttle then the prop and fuel mix is right. I will try and remember to tach my combo Friday and post the #
These engines do not really like to be reved high, but shine when loaded down. I think you are too focused on static RPM, If the plane is trying to rip it's self from your hands when held up @ full throttle then the prop and fuel mix is right. I will try and remember to tach my combo Friday and post the #
08-03-2007, 02:46 PM
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RE: Engine losing power during loop.. Saito 91
Hello to everyone and thanks for your suggestions and help.... The Edge 540 went airborne today and performed as well as it can with the Saito 100.... Used a 14 X 6 prop and turning about 9700 rpm's static.... a friend that flies pattern airplanes took her off and did a loop... It seems that while many factors may effect this design of airplane in doing a simple loop there was one main factor that was present today and everyday that I have tried to do a loop... It was the throws on the elevator... I had everything set as I would most of my airplanes and that would be about 3/4 inch max.. 45% expo and dual rates at 60%/100%.... He flew at low rates of 60%... As he did the first loop he commented that I had way too much throw in the airplane.. both aileron and elevator..
He used about 1/8 inch movement in the stick and she did a plain average loop... He did this twice and then he ask me to watch as he give a full pull to the elevator to do a loop... It went up and stalled at the top....! Just like all of my flights with both engines including the 91 Saito and several different props... It appears to be a design feature in this airplane as you can not be handed and jerk the airplane throught a loop... I was expecting this design to perform as does my 60 Stinger with a 90FS Magnum, my Super Sportster with a 70 FS O.S. and my Four Star 60 with an O.S. 90 FS... In fact all 12 of my airplanes with both 2 stroke and FS, Bipe's and mono have all flown and loop with my style of flying and set ups... I tend to go mild and easy with the throws but have a tendence to pull full back at anytime during the loop althought I like large loops with gentle back pressure on the stick..
This experience may not be the same for others and with different engines but it shows how a simple easy manuver can be difficult if you do not understand the airplane...Thanks for all of your time and efforts...
He used about 1/8 inch movement in the stick and she did a plain average loop... He did this twice and then he ask me to watch as he give a full pull to the elevator to do a loop... It went up and stalled at the top....! Just like all of my flights with both engines including the 91 Saito and several different props... It appears to be a design feature in this airplane as you can not be handed and jerk the airplane throught a loop... I was expecting this design to perform as does my 60 Stinger with a 90FS Magnum, my Super Sportster with a 70 FS O.S. and my Four Star 60 with an O.S. 90 FS... In fact all 12 of my airplanes with both 2 stroke and FS, Bipe's and mono have all flown and loop with my style of flying and set ups... I tend to go mild and easy with the throws but have a tendence to pull full back at anytime during the loop althought I like large loops with gentle back pressure on the stick..
This experience may not be the same for others and with different engines but it shows how a simple easy manuver can be difficult if you do not understand the airplane...Thanks for all of your time and efforts...
