2008 the year of the Turbinator
08-30-2022, 11:43 PM
#851
I fly my Turbo now and then, the last time that it took off the ground it surprised me big time and, I learned from that!!
Kind of a breeze day it was, I decided to TO with the flaps 1 position, this time no smoke fluid, that made a big difference on this TO run, the run was very short, it got off the ground in a hurry and too slow, it headed for the pits, I was very surprised it was doing that, I manage to swing it back to the runway, it decided to ride the top of the fence first before dropping off to the runway nose first then the right wing tip followed, it sat there like nothing has happened.
I began to scratch my head asking myself, what in the world had just happened? 🤯 after so many perfect TOs what in the world changed?
My analysis: since I opted to install a set of T45 trailing struts instead of the straight ones recommended by Nick ( designer ) I concluded that, on the ground the trailing struts configured the Turbo in a nose up TO position ( a la F100 ) with the strong breeze and no smoke fluid in the 40 oz tank, it it took off right away at the slowest speed possible, like that it was hard to control its direction ( I have never seen it that slow ) had I added the 40 oz of smoke fluid, the TO would have been normal as many times before, live and learn 🤷♂️
Here is the new nose, well, soon to be 🙄
Kind of a breeze day it was, I decided to TO with the flaps 1 position, this time no smoke fluid, that made a big difference on this TO run, the run was very short, it got off the ground in a hurry and too slow, it headed for the pits, I was very surprised it was doing that, I manage to swing it back to the runway, it decided to ride the top of the fence first before dropping off to the runway nose first then the right wing tip followed, it sat there like nothing has happened.
I began to scratch my head asking myself, what in the world had just happened? 🤯 after so many perfect TOs what in the world changed?
My analysis: since I opted to install a set of T45 trailing struts instead of the straight ones recommended by Nick ( designer ) I concluded that, on the ground the trailing struts configured the Turbo in a nose up TO position ( a la F100 ) with the strong breeze and no smoke fluid in the 40 oz tank, it it took off right away at the slowest speed possible, like that it was hard to control its direction ( I have never seen it that slow ) had I added the 40 oz of smoke fluid, the TO would have been normal as many times before, live and learn 🤷♂️
Here is the new nose, well, soon to be 🙄
Last edited by CARS II; 08-31-2022 at 09:14 AM.
09-30-2022, 01:30 AM
#854
Hi all,
I have a 80 size turbine for the Z Turbinator,
It's not entirely clear to me at what angle I should mount this in the fuse, can someone help me?
I used the search function but didn't really find anything.
Best regards,
Ruud,
I have a 80 size turbine for the Z Turbinator,
It's not entirely clear to me at what angle I should mount this in the fuse, can someone help me?
I used the search function but didn't really find anything.
Best regards,
Ruud,
09-30-2022, 06:24 AM
#856
09-30-2022, 11:41 AM
#857
Understandable supposition, but fortunately not the case. As the thrust (or more precisely, the eflux) of any given turbine(s) varies from idle to full blow, so does its influence on the horizontal stab. More blow underneath the stab = more upward pitch moment from the stab.
While a partial purpose of angling the exhaust downward is to move the eflux away from the stab, the bigger aim is to create a nose-down moment from the thrust which varies with that thrust at a rate equal to the eflux’s influence on the stab. Ideally there’s an angle where those two factors are in concert and cancel each other out regardless of the eflux/thrust produced.
Question: Is this the Schulman ARF version, or kit-built?
While a partial purpose of angling the exhaust downward is to move the eflux away from the stab, the bigger aim is to create a nose-down moment from the thrust which varies with that thrust at a rate equal to the eflux’s influence on the stab. Ideally there’s an angle where those two factors are in concert and cancel each other out regardless of the eflux/thrust produced.
Question: Is this the Schulman ARF version, or kit-built?
09-30-2022, 11:53 AM
#858
The bottom line is that with a variety of models including the Turbs and Reactions, 4-5 degrees is about right, or at least very close. This post Other Turb Thread in another thread shows the approximate angle that has worked for others. I think that if you start out in that ball park you can’t go very wrong and will be close enough that a washer or two worth of shimming adjustment later will be all that’s needed to perfectly suit your taste.
09-30-2022, 11:58 AM
#859
Okay clear...
I'm working on the Ziroli laser kit.
I regularly read that with a more powerful turbine the angle should be a bit more to counteract the rise of the model at full throttle.
Only I don't read anywhere how many degrees it should be.
I follow the angle indicated for the schulman turbinator topic...
Thank you for the info..
I'm working on the Ziroli laser kit.
I regularly read that with a more powerful turbine the angle should be a bit more to counteract the rise of the model at full throttle.
Only I don't read anywhere how many degrees it should be.
I follow the angle indicated for the schulman turbinator topic...
Thank you for the info..
Last edited by redcesar; 09-30-2022 at 12:37 PM.
09-30-2022, 12:45 PM
#860
…In that case then I’d start with 3 deg down as per the drawings and shim in more later if needed. I used 4-ish deg down on two similar scratch-builds -one of which has a full 50% more thrust than the other- and both models have zero pitching moment with their respective throttles set anywhere from 30% thru 100%.
IMO, don’t sweat it. I doubt that you’d be very far off if you went with 3,4, or 5 degrees, and whatever you select is easily adjusted afterward.
IMO, don’t sweat it. I doubt that you’d be very far off if you went with 3,4, or 5 degrees, and whatever you select is easily adjusted afterward.
Last edited by highhorse; 09-30-2022 at 05:12 PM.
09-30-2022, 12:57 PM
#861
Agreed with highhorse 100%.
I also had the same question when I was building mine, Ziroli flew his proto Turbo with a 15 or 16 lbs thrust turbine.
I ended up building the engine mount per the plans, I'm running a P80 in mine ( 18-19 lbs thrust ) tested it many times in flight, flies just fine at all speeds, no need to adjust the turbine angle.
There you have it.
Note: the thrust angle is like the CG point, it is a good point to start with then, after a few flights, it can be adjusted to your liking, my Turbo didn't needed any thrust angle adjustment and the position ( angle ) of the turbine is where I like it.
I also had the same question when I was building mine, Ziroli flew his proto Turbo with a 15 or 16 lbs thrust turbine.
I ended up building the engine mount per the plans, I'm running a P80 in mine ( 18-19 lbs thrust ) tested it many times in flight, flies just fine at all speeds, no need to adjust the turbine angle.
There you have it.
Note: the thrust angle is like the CG point, it is a good point to start with then, after a few flights, it can be adjusted to your liking, my Turbo didn't needed any thrust angle adjustment and the position ( angle ) of the turbine is where I like it.
Last edited by CARS II; 09-30-2022 at 01:04 PM.
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1Eye (10-01-2022)
10-01-2022, 09:52 PM
#864
I would strongly advice against that set up. It would probably cause a significant "nose down" force when power is applied and you certainly don’t want that. I suggest that you stick to the angle that is built in to the original construction and that is specified in the plan. The engine in this model is situated near the centre of aerodynamic pressure and therefore there is no need to complicate things.
10-02-2022, 02:39 AM
#865
I would strongly advice against that set up. It would probably cause a significant "nose down" force when power is applied and you certainly don’t want that. I suggest that you stick to the angle that is built in to the original construction and that is specified in the plan. The engine in this model is situated near the centre of aerodynamic pressure and therefore there is no need to complicate things.
Yes i think that is the best way to go, thank you for your reply.
If the model tends to pitch up at full throttle I can always mix some throttle to elevator.
Regards,
Ruud.
Last edited by redcesar; 10-02-2022 at 02:50 AM.
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Jannica (10-02-2022)
10-02-2022, 10:52 AM
#867
Thanks everyone for the tips!
Last edited by redcesar; 10-02-2022 at 10:59 AM.
10-02-2022, 12:10 PM
#868
Junior Member
Hi
I build in about 10 degree on mine and it fly ok, had to do some adjustment of cg after the first flights to get it right.
Not sure, maybe it would work just fine with the original setup.
I build in about 10 degree on mine and it fly ok, had to do some adjustment of cg after the first flights to get it right.
Not sure, maybe it would work just fine with the original setup.
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Summit66 (02-02-2023)
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Summit66 (04-24-2023)