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Author Topic: The Warsaw Cup and the World Championships 2022 - my own perspective  (Read 2013 times)

Offline Matt Piatkowski

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Hello,
I was there as an "independent press" and decided to share my findings and opinions with you.

I watched the best F2B pilots and their techniques and I was not disappointed.

These are my opinions:
1. There were three F2B grass circles prepared by the organizers. Two main circles were on the NE side of the hangar and one on the East side of the airfield of the Kruszyn Aero-club, about 900 m from the main circles. The quality of grass on main circles (A and B) was, unfortunately, not to the FAI standards. The quality of grass on the third circle was even poorer. Organizers simply did not have enough money to hire a professional team to slowly prepare the grass of very good quality. The cash inflow, provided by a smaller number of nations and participants, was barely sufficient to organize the events at all. Simply put: it was either the compromise or nothing. The organizers selected a compromise and I fully agree with this approach. No F2B plane broke the landing gear and all F2B competitors had some points deducted for take-off and landing.

Conclusion re: quality of grass. FAI's definition of quality is great but this sport has to face the grim reality of 2022. Inflation, high costs of any labor, gas, and energy, lack of countries willing to organize the events of this proportion, and, lastly,  political and military chaos initiated by the invasion of Ukraine. I feel we all should be grateful to the polish organizers that they managed to do it.

2. F2B models: about 70% factory made. From Yatsenkos, Solomianikov, Leonidov and Astrakharchik. About 80% were powered by electric motors. In the WChamps F2B finals (15 competitors), there was a single glow-powered model (Yatsenko's YAK).

Conclusion re: models. There will be more and more factory-made models in the years to come. AMA BOM rule does not apply in the FAI F2B competitions and the top pilots have simply more time to practice the pattern instead of sanding. Some fly more than 1000 flights per year and the effects are visible.   

3. The most interesting competitors: Zbynek Kravcik (CZE) and Xu Letong (CHN). Zbynek flies his own design (Zlin) and Xu Letong - Yatsenko's Max Bee R3. Zlin is made using the partial vacuum bagging technique and Zbynek should congratulate himself for building such a wonderfully flying F2B model. Patrik Dolobac (SVK) also made an impression. He belongs to Igor Burger's F2B Team that won the team gold.

4. The contra and Polish Team: Three models with the GAU/D geared contra in the WChamps and two in the finals (Borzecki and Miesiak). Marek Rakowski (11 place overall), used a single motor with the 4-blade "ventilator" prop. He will switch to either GAU/D or TMT R contra next season. In the Warsaw Cup, there was a model with the TMT R contra by Robert Tomzik. I have this power plant and will, hopefully, fly in the F2B 2023 competitions in the EU. Assuming of course the hordes from the East will be tamed...

5. Technique: Orestes Hernandez, Zbynek Kravcik, Sergii Solomianikov, Patrik Dolobac and Konstantin Baj. are my picks. Clean, crisp, efficient, and effective. The "handle position" in the inverted horizontal flight and its impact on the quality of loops was an interesting addition to the subject.
    Xu Letong (CHN) moves his entire body up and down (partial squats while finishing the bottoms of maneuvers) but he flies very well.
    Conclusion: there is more than one way to fly the pattern well. In my opinion, the guiding principle should be energy conservation 
    and the pilot's stability. I will write more about the pattern technique when I finally learn to fly the pattern on the 1000 FAI points level.
    This may or may not happen: I am aging and my flying is a race with time. If I will not make it, I will say to myself: "at least I tried".

I truly enjoy meeting the American Team and having open discussions about techniques with Orestes.
 

Talking to other teams (except Polish of course ) was a bit challenging. Many excellent pilots could not communicate in English well enough to exchange highly technical details I usually inquire about. Some were evasive...

Lastly: the weather. On the 10 points scale, I would give it 9. Some rain and soft hail on Tuesday, Aug.09, was a short interruption and the flying resumed. Final days: definitively 10 points - not too hot, moderate wind, some thermal wind but almost no ground level turbulence. Everybody flying in the finals could concentrate 100% on flying instead of running around to maintain the line's tension.

Best Regards,
Matt Piatkowski

P.S: My wife and I are still living in two countries. Let me assure you that this stunt is equally difficult as flying the pattern better than Igor Burger.

Online Peter Germann

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Re: The Warsaw Cup and the World Championships 2022 - my own perspective
« Reply #1 on: August 14, 2022, 04:39:00 AM »
quality of grass. FAI's definition of quality is great but this sport has to face the grim reality of 2022. Inflation, high costs of any labor, gas, and energy, lack of countries willing to organize the events of this proportion, and, lastly,  political and military chaos initiated by the invasion of Ukraine. I feel we all should be grateful to the polish organizers that they managed to do it.

Dear Matt
Thank you for your thorough, personal analysis of the World Championships in Poland. I would like to take this opportunity to express my thanks and great respect to the organizers in Poland for the organization and running of the event. In particular, the very good, ongoing transmission of the results almost in real time was a great achievement.

As far as the condition of the F2B circles is concerned, you mention financial reasons as the cause of the insufficient quality of the surfaces. In my opinion, this is fundamentally unacceptable because compliance with binding FAI rules at a World Championships must not be dependent on money to pay for acting as required by the book. If a problem arises from this, it must be solved by the organizer, and in case of doubt, even if the need for higher entry fees arises as a consequence.

With my best regards,

Peter Germann
F2 Subcommittee Member
F2B Working Group Coordinator
Peter Germann

Offline katana

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Re: The Warsaw Cup and the World Championships 2022 - my own perspective
« Reply #2 on: August 14, 2022, 05:01:45 AM »
Peter, that's a nice sentiment but in these difficult times its hard to justify! I'm sure the Polish Authorities wouldn't have even considered the ridiculous rampant worldwide inflation effect on costs of not only them but potential competitors when they bid for / accepted the responsibility. Likewise the effects of conflict not of their making boardering their country. Many countries sent smaller / no teams whatsoever (for whatever reasons) so income stream would be depressed. If the FIA set the standard they should stand behind it with financial assistance to ensure it can be achieved - if not, the organisers could just hold their hands up, say we can't do what you want, so the event is cancelled! You can't blame the hosting club - its a potential huge moneyspinner or car crash for their finances. the latter could close them down so of no benefit to anyone!

Offline Keith Renecle

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Re: The Warsaw Cup and the World Championships 2022 - my own perspective
« Reply #3 on: August 14, 2022, 05:54:59 AM »
Hi Matt,

Thanks very much for your good feedback on the F2B events. That is a good summary of how things have developed in stunt over the last 10 years or so with the dominance of RTF models. There are obvious advantages, especially for the less experienced builder's but personally I feel that we have also lost much in the process.

However, I totally agree with Peter's sentiments! There is zero excuse as far as I'm concerned about the condition of the flying circles. This goes back to 2014 when they hosted their last world champs. At that time there was a huge protest from most of the team managers. If they started planning just after that for the 2020 event, then they had 6 years to sort out the problem. They cannot say that they did not know......they HAD to know! There was ample time then to make better plans for two good grass circles. There was also no real practice field in 2014, and I feel that the organizers could have at the very least arranged for the use of a few nearby sports fields, like other nations have done before.

Other than that it seems that there are many other positives to take away, and without many of the "Big Guns" in all categories, there were many chances for others to shine which will encourage these competitions to do even better next time.
Keith R

Offline PerttiMe

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Re: The Warsaw Cup and the World Championships 2022 - my own perspective
« Reply #4 on: August 15, 2022, 01:10:50 AM »
Contraprops make me curious.
- easier to trim for consistent flying, or just easier to fly (period)?
- Or just the "latest idea" that makes you feel good about your model?
I suppose you need to be pretty good anyway, before seeing and feeling any advantages.
I built a Blue Pants as a kid. Wish I still had it. Might even learn to fly it.

Offline Lauri Malila

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Re: The Warsaw Cup and the World Championships 2022 - my own perspective
« Reply #5 on: August 15, 2022, 03:37:51 AM »
Pertti,

To me it looks that the model does everything more symmetrically, outside vs inside, that is. That happens when parasitic effects of torque and gyroscopic actions are compensated or eliminated.
But the system is quite noisy, I don’t know if it is caused by props or the gear mechanism. Propably both. It would be interesting to see (or rather hear) more variations of the same theme, a belt drive or 2 separate motors, for example. Or at least some serious help in vibroacoustics. L

Online Dennis Toth

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Re: The Warsaw Cup and the World Championships 2022 - my own perspective
« Reply #6 on: August 15, 2022, 06:51:31 AM »
Matt,
Thanks for the interesting article. Hope the next WC host gets some take-a-ways from this year and plans accordingly.

When you get a chance could you post, maybe in a separate thread, some information on the Contra prop setups.

Best,   DennisT

Offline Paul Walker

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Re: The Warsaw Cup and the World Championships 2022 - my own perspective
« Reply #7 on: August 15, 2022, 12:32:13 PM »
 Propably both. It would be interesting to see (or rather hear) more variations of the same theme, a belt drive or 2 separate motors, for example. Or at least some serious help in vibroacoustics. L
[/quote]

I have run borh. Each has a different set of issues keeping me from using either at this time.

Geared system. It does make some noise. Mostly gear noise. However  the gears and props are too fragile.  The two motor system is a lot heavier  and makes way more prop noise.  Did either make flight way better. No. I still prefer the system I use noe.

Will experiment more with the geared system to see if the fragility can be improved.

Offline Brett Buck

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Re: The Warsaw Cup and the World Championships 2022 - my own perspective
« Reply #8 on: August 15, 2022, 12:37:16 PM »

Will experiment more with the geared system to see if the fragility can be improved.

    What are the gears made of?

    Brett

Offline Steve Helmick

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Re: The Warsaw Cup and the World Championships 2022 - my own perspective
« Reply #9 on: August 15, 2022, 12:41:05 PM »
Hello,
I was there as an "independent press" and decided to share my findings and opinions with you.

I watched the best F2B pilots and their techniques and I was not disappointed.

Elsewhere, I read that there was only one member of the Canadian F2B Team. I can't imagine why you didn't opt to enter as a Canadian.  ???   
"The United States has become a place where professional athletes and entertainers are mistaken for people of importance." - Robert Heinlein

In 1944 18-20 year old's stormed beaches, and parachuted behind enemy lines to almost certain death.  In 2015 18-20 year old's need safe zones so people don't hurt their feelings.

Offline Lauri Malila

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Re: The Warsaw Cup and the World Championships 2022 - my own perspective
« Reply #10 on: August 15, 2022, 12:44:51 PM »
 Paul,

 Sorry, a little silly question. I'm just curious:
 Apart from noise and weight and fragility, how did you decide that it doesn't improve the way your model flies? Did you convert a normal model or build something all-in-line? L
 

Offline Lauri Malila

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Re: The Warsaw Cup and the World Championships 2022 - my own perspective
« Reply #11 on: August 15, 2022, 12:48:27 PM »
    What are the gears made of?

    Brett

 I talked with Pawel, and it seems that material choises are ok, always metal-plastic contact. 0,7 module. L

Offline Paul Walker

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Re: The Warsaw Cup and the World Championships 2022 - my own perspective
« Reply #12 on: August 15, 2022, 06:40:43 PM »
    What are the gears made of?

    Brett

The ones that fail are some kind of plastic. The design of the gear looks too fragile. Very many teeth  but VERY narrow, with no shear strength to speak of.

Offline Paul Walker

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Re: The Warsaw Cup and the World Championships 2022 - my own perspective
« Reply #13 on: August 15, 2022, 06:57:26 PM »
Paul,

 Sorry, a little silly question. I'm just curious:
 Apart from noise and weight and fragility, how did you decide that it doesn't improve the way your model flies? Did you convert a normal model or build something all-in-line? L

Well, that is a very interesting question
 The dual motor system actually fit in one of my current Impacts. I had a discarded fuse that was made to fit it. That one flew, but the performance was not as good as the hollow 12 inch Igor prop. It might be influenced by the higher weight though.

The geared system would not go in any of my front line fighters. I found that I could make an adaptor to fit my first purpose builf electric plane, and that is where I started. What I found odd was that it had less line tension with this system going slightly faster.

Then I devised a way to get it my first P-47. An elaborate system of carbon plates allowed it to reside there. I have a fair number of flights on it  and was going to start adding tail weight to get it to fly better. I ran out of time and had to start practicing eithy US Nationals plane.

Both systems make more noise than I like. The geared system is quieter, and I believe it is because the two props are farther apart on it.
For me, its not the solution at this point. Given more time...???
« Last Edit: August 16, 2022, 07:59:11 AM by Paul Walker »

Offline Matt Piatkowski

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Re: The Warsaw Cup and the World Championships 2022 - my own perspective
« Reply #14 on: August 17, 2022, 02:24:39 AM »
Hello,
My response to Peter G. and Keith R. messages: the issue of grass quality will stay with us in the years to come. Maybe the main problem is not the money but proper and effective management of the problem?

My response to Lauri M. message: like you wrote, the power plant with counter-rotating propellers eliminates the gyroscopic moment acting on the model in turns. If you fly a model with a single propeller for many years and then switch to contra, the first impression is that the model flies like riding on rails: there in no roll and yaw in turns. Immediate improvement is visible in crispiness of the triangle,  9th. and 10th. corners of the horizontal eight, and 2nd. and 3rd. corners of the hourglass. The noise issue: the geared contra ( I call it GAU/D) is louder than the Two-Motors-in Tandem contra (TMTR). During the Warsaw Cup, I have measured the noise of two models: one had the GAU/D contra, the other - TMTR contra. Both models had identical plan form. The one with the TMTR contra was 45 grams heavier (1830 grams.) From a distance of about 6 meters, the highest noise of GAU/D contra was 73-74 dBA. and the TMTR contra - 68-69 dBA. Both models used the same propellers (12x6 wide blade from Tomek Jadczak). I could not record the frequency spectrum, but it is not necessary. A-weighted decibels, abbreviated dBA, or dBa, or dB(a), are an expression of the relative loudness of sounds in air as perceived by the human ear.. In other words: you tell me some noise is loud for you because this is how you perceive it.

Lastly: GAU/D contra has the 25 mm. gap between propellers, TMTR contra - 32 mm. It is the main reason for less dBA in TMTR.
Ref: multiple publications in Germany, Great Britain, USA and Soviet Union during 1944-1962 era.
Please see my answer to Paul W. message for more.

My response to Dennis: I will send you the setup for the TMTR contra on two 12x6 wide PolProps with two Spin 44 F2B controllers and the Fiorotii active timer. This setup was not checked yet in flight because I do not have the model available. The TMTR ground tests results are, however, available.

My response to Paul W. message: please see my response to Lauri's message regarding the relative noise level of both existing contra power plants. RTF weight: the weight penalty for using the TMTR contra is about 60 grams. I wrote about, because the GAU/D power plant is evolving, but changes are kept secret by developers. There is no secret in the TMTR contra, though. It is one of the reasons I have selected TMTR for my next full - size F2B model. Assuming this model must weight RTF below 1800 grams, the complete structure with landing gear, covered and finished, must weight about 960-980 grams. It is challenging but possible if the builder thinks contantly about weight savings while building the structure. The best examples of such approach are beautiful models hand-made by Krystian Borzecki.

My response to Steve: I wanted to represent Canada but was not allowed. John McFayden wrote:"Matt, I cannot add you to the team as a walk-on. Just against the rules. I did check with a couple other CLPA Committee members to confirm." No further comments.

Best Regards,
M


Offline Brett Buck

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Re: The Warsaw Cup and the World Championships 2022 - my own perspective
« Reply #15 on: August 17, 2022, 10:09:41 AM »
The ones that fail are some kind of plastic. The design of the gear looks too fragile. Very many teeth  but VERY narrow, with no shear strength to speak of.

     Given the power levels, and the extra load and in-plane vibration of the props passing close to each other, I would think it would take a pretty impressive gear train to take it for long. I don't see any practical way to put in an isolator- since the frequency is relatively low, it would have to be really soft, but still has to handle 1/2 the power level + a bunch of margin + the vibration it is isolating.

      The few reduction-gear systems that I saw work for any length of time, the delrin gears were maybe 1/2" thick at the face and those didn't have to handle anything like the in-plane vibration you get with the contra-rotation.

 
    Brett

Offline Brett Buck

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Re: The Warsaw Cup and the World Championships 2022 - my own perspective
« Reply #16 on: August 17, 2022, 11:37:27 AM »
My response to Peter G. and Keith R. messages: the issue of grass quality will stay with us in the years to come. Maybe the main problem is not the money but proper and effective management of the problem?

    OK, I want to stay out of FAI matters, but my head is exploding!

    So,  wave the white flag on having acceptable fields, but "proper and effective management" somehow fixes the problem? What, in precisely and exact detail,  would you "manage"?  What in the heck to you expect to change about it?

    Isn't this the same site it was in 2014?   If so, why was a bid accepted in the first place?  And you expect the same "management" regime to suddenly see the error of their ways?

    Of course, these questions are rhetorical, you are absolutely right - we already know what will be done to prevent the recurrence of the same problem in the future - absolutely nothing. From their perspective they are doing A-OK!  The management *is* the problem, not the solution. You cannot expect the same people and organization that allows this repeatedly for years to fix it for you, you need radical change at the management level. Even if you have to take the matter into your own hands.


     
    Brett

Offline Scott Richlen

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Re: The Warsaw Cup and the World Championships 2022 - my own perspective
« Reply #17 on: August 17, 2022, 12:04:23 PM »
Quote
From their perspective they are doing A-OK!  The management *is* the problem, not the solution. You cannot expect the same people and organization that allows this repeatedly for years to fix it for you, you need radical change at the management level. 

Wow!  Talk about a comment that is, sadly, way too applicable to way too many organizations these days!  How many organizations could you list with entrenched bureaucracies that serve themsleves instead of their claimed constituency?

Don't bother trying to list them, there's just too many.

Offline Howard Rush

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Re: The Warsaw Cup and the World Championships 2022 - my own perspective
« Reply #18 on: August 18, 2022, 02:43:01 PM »
Folks have come up with ways to trim airplanes to compensate for the gyroscopic effect of rotating machinery, but the contra system looks like it makes trimming easier.  The Polish team's planes went through turns with nary a wiggle.  My impression was that the propulsion system didn't hold speed as well as a conventional motor with Igor's 12" prop, but it is hard to tell without flying it.  I didn't see the Polish guys have any propulsion problems.  Either the contra systems are pretty reliable or they change them a lot. 
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Offline Mike Alimov

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Re: The Warsaw Cup and the World Championships 2022 - my own perspective
« Reply #19 on: August 18, 2022, 06:58:17 PM »
Since this thread has evolved into the discussion of contra systems, I have to ask the obvious question.
Assuming that we are trying to solve problems related to the giro precession of the prop (although it didn't seem to bother the top 3 pilots at the Worlds), why introduce all the complexity related to coaxial counter rotating systems if it has been shown that twins do it just as effectively, and introduce some additional benefits too (like more energized airflow over greater span of the wing and tail)?

Offline Howard Rush

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Re: The Warsaw Cup and the World Championships 2022 - my own perspective
« Reply #20 on: August 18, 2022, 07:06:57 PM »
Since this thread has evolved into the discussion of contra systems, I have to ask the obvious question.
Assuming that we are trying to solve problems related to the giro precession of the prop (although it didn't seem to bother the top 3 pilots at the Worlds), why introduce all the complexity related to coaxial counter rotating systems if it has been shown that twins do it just as effectively, and introduce some additional benefits too (like more energized airflow over greater span of the wing and tail)?

Certainly
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Offline Air Ministry .

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Re: The Warsaw Cup and the World Championships 2022 - my own perspective
« Reply #21 on: August 18, 2022, 08:13:22 PM »
Youd think a surface unsuitable for operateing ' wheel pants ' would be totally unacceptable for a WORLD CHAMPIONSHIP .

Penalty Clause for non compliance ?

Surely Europe is littered with reasonably flat ' car parks ' ( Hard Surface ) . Most Euro CLUBS would have better fields ? if not as multitudinous circles ? ?

Seems it cheapens the general impression of the event .

Teodorico Terry

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Re: The Warsaw Cup and the World Championships 2022 - my own perspective
« Reply #22 on: August 22, 2022, 06:48:42 AM »
Contra systems have been around in F3A (R/C pattern) for some time now and there are two flavors.  The Brenner contra uses a differential gear set and the others in which the props are geared directly off the motor. In both cases they use small helicopter motors spinning at very high RPM to deliver the power needed to fly a 11 lb model with unlimited vertical. The Brenner system uses all metal gears whereas the other systems use a combination of delrin gears and toothed belts. They both work well although the Brenner systems appeals to me because of the differential gear set.  I believe that it is more efficient because of the manner in which the props can share the load (there is no unloaded prop). The other thing to keep in mind is that the rear prop is generally of higher pitch since it is being fed air at a slightly higher velocity. By relying on smaller motors the added weight of the gear set, extra prop, etc. is mitigated to a degree; however, they are still heavier than a conventional set up.

Teo
« Last Edit: August 22, 2022, 08:11:45 AM by Teodorico Terry »

Online Bob Hunt

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Re: The Warsaw Cup and the World Championships 2022 - my own perspective
« Reply #23 on: August 22, 2022, 10:07:43 AM »
Since this thread has evolved into the discussion of contra systems, I have to ask the obvious question.
Assuming that we are trying to solve problems related to the giro precession of the prop (although it didn't seem to bother the top 3 pilots at the Worlds), why introduce all the complexity related to coaxial counter rotating systems if it has been shown that twins do it just as effectively, and introduce some additional benefits too (like more energized airflow over greater span of the wing and tail)?

Spot on Mike! In my personal experience with twins I've discovered that they exhibit almost "jet-like" flight with no gyroscopic ill effects whatsoever. Now, I'm nowhere near an engineer, but I do try and apply what I like to call "Apparent Physics" to my modeling program. I have always believed that I could achieve identical results to those who use actual physics and genuine math (which I flunked in school routinely...) by applying obvious, educated logic to the design and construction of my planes. Yeah, it usually takes me a bit longer than the physics/math guys to get the results I'm searching for, but, hey, that's part of the fun for me.

It just seemed logical to have two motors and props spinning opposite to each other to negate any of the ill effects of a single prop. Also, that single prop is mounted in the fuselage of the model and the spiral airflow is going around the fuselage causing drag and rolling forces on the vertical fin. All that goes away (in my way of thinking) with a twin. And, as Mike wrote, there is the added component of much more disc span (and area) to provide accelerated air over the surfaces resulting in much more lift. And, indeed, the twins fly much "lighter" than they actually are due to this factor. Add to this also the fact that you can have all that additional disc span and area without the attendant longer gear that is required with a large diameter single prop on a single engine/motor plane. That means less vertical CG issues. I'm very convinced that twins are going to be seen more and more as fliers experiment with them.   

Later - Bob Hunt

 

Offline PerttiMe

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Re: The Warsaw Cup and the World Championships 2022 - my own perspective
« Reply #24 on: August 22, 2022, 10:53:58 AM »
...
It just seemed logical to have two motors and props spinning opposite to each other to negate any of the ill effects of a single prop. ...

Later - Bob Hunt
Does it make a difference which way the props turn?
I recall there was a drastic difference on a WW2 twin fighter.
I built a Blue Pants as a kid. Wish I still had it. Might even learn to fly it.

Offline Trostle

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Re: The Warsaw Cup and the World Championships 2022 - my own perspective
« Reply #25 on: August 22, 2022, 12:52:10 PM »
Does it make a difference which way the props turn?
I recall there was a drastic difference on a WW2 twin fighter.

The P-38 had problems with props turning the same direction.  It was found that the airplane performed better with the top of the props turning outward rather than inward.

The same process for the deHavilland Hornet, except it was found that the airplane performed better with the top of the props turning inward.

I have material that explains the findings and results during the test programs for both of these aircraft.  If I remember correctly, it had something to do with the propwash over the tail plane, the difference coming from the twin boom configuration of the P-38 and the more conventional twin configuration of the Hornet.  (I think it is safe to say that both of these designs were considered high performance aircraft in their day.)

It would be interesting what Bob Hunt has found with his twin.

Keith

Offline Mike Alimov

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Re: The Warsaw Cup and the World Championships 2022 - my own perspective
« Reply #26 on: August 23, 2022, 08:00:26 AM »
I would also be interested to see how the total Powertrain weights stack up between a single and twin versions. For a single motor system (typical full size stunt ship, say 670 squares and mid-60 oz), one would be hard pressed to come up with less than a 19-20 oz package- that includes motor, battery, ESC, timer, wiring. What about twin?

Offline Air Ministry .

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Re: The Warsaw Cup and the World Championships 2022 - my own perspective
« Reply #27 on: August 24, 2022, 07:44:34 PM »
Intresting thing with a lectrick twin , is seperating the ( main ) weight & THRUST , as in the motor , tank , muffler etc - equivilant to the full ELEC. SYSTEM WEIGHT , isnt necesarrily in the nacelles . unlikely in the nacells
even . Just the Elec. Motor weight . And in ' Multi engined ! .

As in the main weight , batterys particularly . and controllers ? etc are on the fuse center & movable as TRIM Weight . !  :P Where I. C. E.  ALL the weight is outboard on the wings . Unless your Paul Walker ! .



One can always argue for load / span distribution though .  VD~

Has anyone thought it through & figured the pro's & con's either / each way  ( weight central Vs weight in Nacelles )
Just to rub it in , a Brabazon was pre ' thin wing ' tecnology . or THEY were anyway . So scale the wings as thick as a fiddle ! and the nose is really long so you could use really light batteries .  %^@


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