Author Topic: Wind Tolerant Power (Read 3195 times)

ash · « **on:** February 03, 2011, 03:07:01 AM »

Before I took my 3-year break from toy planes I was working on a couple of designs to test various theories on wind and turbulence tolerance. One model to handle the turbulence and one to handle dead air. Interestingly threads on exactly this have popped up just as I get back to developing my designs.

Something I didn't think too much about back in '08 was how to power these beasties... provisionally I decided on a piped 36 (a la PTG) for the wind model and either a 4-stroke or a big, dumb muffled 2-stroke for the calm air model. More than any attempt to handle the rare occurence of dead air, the calm air model is more of a control in the experiment. Very conventional and equipped to contrast the specific features of the wind/turbulence model. On that basis, maybe they should both have the same power system? Maybe not...

So, two things to ponder:

1. What do you think is the ideal engine system to handle high winds, wind-up etc? (Ignoring electric for now and also ignoring the details of the model, engine size etc. Lets keep it generic - piped/muffled, 2-stroke/4-stroke, 2-2/4-4/4-2, conventional/big cubes, prop style, pressure, tank etc...)

2. Which systems have you found or observed to be unsatisfactory when the wind gets up? What do they do wrong?

Brett Buck · « **Reply #1 on:** February 03, 2011, 05:01:17 PM »

Quote from: ash on February 03, 2011, 03:07:01 AM

1. What do you think is the ideal engine system to handle high winds, wind-up etc? (Ignoring electric for now and also ignoring the details of the model, engine size etc. Lets keep it generic - piped/muffled, 2-stroke/4-stroke, 2-2/4-4/4-2, conventional/big cubes, prop style, pressure, tank etc...)

2. Which systems have you found or observed to be unsatisfactory when the wind gets up? What do they do wrong?

Pipe with low pitch (3.5-4").

Brett

proparc · « **Reply #2 on:** February 03, 2011, 05:02:26 PM »

Miserable, retched excess!!!

PJ Rowland · « **Reply #3 on:** February 03, 2011, 08:56:04 PM »

I had AMAZING success with my .61 powered Nobler in High winds.

A: The nobler handels wind extremly well. - I Suspect wing thickness as a key ingredient -
B: It delivered thumping low Torque and Controlled speed perfectly even in 25 + Winds - Lots of confidence.

Randy Powell · « **Reply #4 on:** February 04, 2011, 07:26:32 PM »

Plettenberg

Howard Rush · « **Reply #5 on:** February 04, 2011, 10:59:52 PM »

Quote from: Randy Powell on February 04, 2011, 07:26:32 PM

Plettenberg

Ash says to ignore it for now. I wish I could.

john e. holliday · « **Reply #6 on:** February 05, 2011, 08:33:20 AM »

Ash, it all depends on who you talk to and which part of this great land they are from. I watched videos where it was stated that a piped engine was the engine of choice because it would power thru the wind. I vaguely remember at the one stunt siminar in which he came to Topeka KANSAS. Someone asked him about the different winds we sometimes get here. I think he said use a low pitch for wind and a higher pitch for calm. I don't fly enough to tell, so I go with what plane I have set up for the contest of the day. The last contest I flew, the P-39 got blowed out of the first maneuver. It was set too rich but felt good in level flight. Did not make a second attempt that day. Now the same day my Primary Force minus a tire on out board flew the pattern with an LA .25 and APC 10-4 prop. By the way the P-39 is LA .46 powered with a 11.5 X 4.5 supposedly miricle prop. So basically, I say set your equipment up and fly it in all conditions.

Bill Little · « **Reply #7 on:** February 05, 2011, 10:05:06 AM »

I would agree that the low pitch prop set up seems to work the best. Around 4 pitch at a higher rpm (9800-10,000 plus).

I watch Bob baron beat Billy Werwage at the '96 NATS. Last time the ST .60 won (I know the Discovery Retro won since then, but I wasn't there and don't know the conditions present) our NATS. Bob Baron was REALLY "ON" all week. Hard to expect anyone to be flying better. In the finals, the first flight was fairly calm and Bob put up an great flight. Billy put up a very good flight. (it's all relative) The wind picked up, progressively, for each succeeding flight. Bob's scores dropped slightly each flight, Billy's stayed about the same, and picked up a bit, IIRC. Bob won, basically with is gap established on the first flight, and Billy just couldn't "improve his scores" enough to overtake Bob. The power train differences I witnessed lead me to believe Billy's set up dealt with the wind and changing conditions better. But Bob's "flying" was just too good that week.

It all depends. But I (and my son) decided to stick with piped power ever since for the "PAMPA class planes". And it does appear to make a difference. Ultimately, it's the guy on the handle who controls the final outcome in a lot of cases.

Big Bear

proparc · « **Reply #8 on:** February 05, 2011, 04:30:28 PM »

Quote from: Bill Little on February 05, 2011, 10:05:06 AM

I would agree that the low pitch prop set up seems to work the best. Around 4 pitch at a higher rpm (9800-10,000 plus).

Last time the ST .60 won
Big Bear

2010 Richard Kornmeier World Champion ST60.

ash · « **Reply #9 on:** February 05, 2011, 06:05:23 PM »

Thanks for the comments so far, guys.

I'm not at all surprised that piped/low pitch or electric are the first answers, but I was expecting some solid support of 4-strokes as an anti-wind-up solution, closely followed by people who tried them and didn't like them.

Four-stroke guys, what say you?

Big dumb 2-smokers are of course the default choice of many over many years, especially outside the USA but it seems to me that pipes and electrics are particularly attuned to steady state operation (of the whole system, not just motor RPM).

Any comments on resistance to up-wind, down-wind variations?

ash · « **Reply #10 on:** February 05, 2011, 06:15:46 PM »

Quote from: john e. holliday on February 05, 2011, 08:33:20 AM

Ash, it all depends on who you talk to and which part of this great land they are from. ...... So basically, I say set your equipment up and fly it in all conditions.

Yes, this is true around the world, also. Pipes and 4-strokes have never taken off here in NZ. France and Italy seem to favour 4-strokes, other parts of Europe prefer muffled 2-strokes, USA are the big users of piped 2-strokes. Australians try a bit of everything.

I like to try a bit of everything, myself. Hence my experiments and by five-model build queue for stunt alone!

The "set up to fly in all conditions" method is probably the wise choice in the long run, but right now I'm trying to isolate certain characteristics of performance with my experimental duo, hence these unending surveys of technical preference.

Brett Buck · « **Reply #11 on:** February 05, 2011, 08:39:26 PM »

Quote from: ash on February 05, 2011, 06:05:23 PM

Thanks for the comments so far, guys.

I'm not at all surprised that piped/low pitch or electric are the first answers, but I was expecting some solid support of 4-strokes as an anti-wind-up solution, closely followed by people who tried them and didn't like them.

4-strokes are pretty much the last thing I think of inhibiting wind-up. They seem to want to have 6-7, even 8" of pitch, and have relatively little feedback, so lots of whip-up

Brett

Bill Little · « **Reply #12 on:** February 05, 2011, 09:06:18 PM »

Quote from: proparc on February 05, 2011, 04:30:28 PM

2010 Richard Kornmeier World Champion ST60.

Hi Milton,

My dear friend, read my post, I am not doing battle in the ST .60 VS. Pipe battle. That is LONG over. I am FULLY aware what Richie did and it was great. I also know (and posted) that Retro Discovery .60s have won the US NATS recently. I posted in that context only.

In the wind, in 1996, Billy's set up "worked" better as it got worse. No "opinion", just a fact. His scores fell off less, and the plane flew better as the conditions worsened in comparison to Bob's. Bob's scores fell, and it was obvious that the plane's performance was suffering.

I also know that Richie had PLANNED on using his ELECTRIC set up, but he wasn't completely comfortable with it yet. I met Richie at the '04 World's, very great young man. And Aaron talked with him quite a bit.

Don't roll the eyes..........

Bill

proparc · « **Reply #13 on:** February 05, 2011, 09:21:43 PM »

Quote from: ash on February 05, 2011, 06:05:23 PM

Thanks for the comments so far, guys.

Four-stroke guys, what say you?

Any comments on resistance to up-wind, down-wind variations?

I consider the Saito 72 to be in a class by itself when it comes to wind tolerant power but, you have to know how to design for the motor. Stick it in a typical 650 class ship, and it will probably not work out.

The "big block" is not so much about wind tolerance, as it is more about demolishing the wind LOL.

proparc · « **Reply #14 on:** February 05, 2011, 09:59:55 PM »

Quote from: Bill Little on February 05, 2011, 09:06:18 PM

Hi Milton,

My dear friend, read my post, I am not doing battle in the ST .60 VS. Pipe battle.

Don't roll the eyes

Bill

Not about ST60 vs Pipe. About the last guy to rock and roll with the ST60. There is no pipe vs. ST60 vs. 4 stroke vs. electric battle. Anything thing that can turn the prop reliability will work. Remember, Igor Burger broke into the top ten at the Worlds with a LA46.

I have never seen an .049 powered stunt ship that can handle strong wind really well because, they just can’t generate the power to weight ratio of say; a PA 65 etc. Behind the low pitch high RPM kind of power is POWER. That is the key!! What makes the Saito 72 so effective in strong wind is brute muscle.

This may shock you but, I don’t think it really matters what you have in the nose, as long as you have a miserable retched excess of it. Whatever Paul Walker’s got in the nose of that 750sq inch Electric Impact is much-much better than the electric setup that powers the other guys 25 class ship, (whatever that is).

The F3A boys started out with the YS 120, then they went to the YS 140, then they went to the YS 160, and now they are at the YS 170-for crying out loud. Their planes are still hovering right around the same 10lbs max. They were never really underpowered in the first place. They were speed constrained, (judges can’t followed them past a certain speed) but, as they started to radically increase their fuselage side area, (carefully study their design progression) they needed more and wind bucking power to maintain track-in short, more drive.

Their planes have more surface area for the wind to work against, than our ships. But unlike us, they are faced with having to try to maintain their orientation to the judges regardless of the wind direction, (we can shift).Powerful piped engines and big block 4 strokes are not about speed, they all about this ”drive”. I have flown low pitch high RPM pipe ships, and they have a “drive” that is very similar to a strong 4 stroke.

Kinetic energy is a big factor in this high drive type of power plant but, I will stop here, so that I don’t hijack the thread, (since you’re the moderator-you know when a thread is being hijacked LOL)

Chris Wilson · « **Reply #15 on:** February 06, 2011, 03:19:41 PM »

Quote from: ash on February 05, 2011, 06:05:23 PM

I'm not at all surprised that piped/low pitch or electric are the first answers, but I was expecting some solid support of 4-strokes as an anti-wind-up solution, closely followed by people who tried them and didn't like them.

Um, I have a few large stunt diesels that would tend to plough through anything that mother nature would throw at them.

They seem to thrive on high pitch props though as it compliments their torque and wind up is never a problem with a diesel.

Cheers.

Andrew Tinsley · « **Reply #16 on:** February 08, 2011, 12:12:32 PM »

Amen to that Chris.
Pity so few people ever tried a big stunt diesel. They run just like a piped motor without the pipe. Maybe heavier than a glow, but use way less fuel so that is about equal. The CG doesn't move as much during the run.
Don't knock it until you have tried it, you may be very surprised.

Regards,

Andrew.

Brett Buck · « **Reply #17 on:** February 08, 2011, 02:15:48 PM »

Quote from: Chris Wilson on February 06, 2011, 03:19:41 PM

Um, I have a few large stunt diesels that would tend to plough through anything that mother nature would throw at them.

They seem to thrive on high pitch props though as it compliments their torque and wind up is never a problem with a diesel.

Cheers.

I don't think it's a matter of plowing through, it's a matter of how much feedback you can get and how easy it is to adjust it. You can plow through with a Saito but there's no easy way to adjust how much feedback you get (that I know of).

I will freely admit I know next to nothing about diesels aside from the fuel smells bad. Do they have a strong load feedback, and how easy is it to adjust? Almost as important - will they do it spinning ~11,000 rpm (in the air)?

Brett

ash · « **Reply #18 on:** February 08, 2011, 02:27:43 PM »

And how easy is it to go to a contest at a new location with different weather/altitude and get a reliable compression/needle setting? If you miss out on practice flights are you going to be in trouble?

Chris Wilson · « **Reply #19 on:** February 08, 2011, 03:23:54 PM »

Quote from: Brett Buck on February 08, 2011, 02:15:48 PM

I don't think it's a matter of plowing through, it's a matter of how much feedback you can get and how easy it is to adjust it. You can plow through with a Saito but there's no easy way to adjust how much feedback you get (that I know of).

I will freely admit I know next to nothing about diesels aside from the fuel smells bad. Do they have a strong load feedback, and how easy is it to adjust? Almost as important - will they do it spinning ~11,000 rpm (in the air)?

Brett

Hi Brett,
Not sure what you mean by 'feedback' here.

But I have used a diesel in the wind before and they definitely are a single speed engine, the gain in revs from ground release to being in the air is only about 500 rpm (and that is about half of what a glow engine is?), they seem to hit a rpm wall in the air anyway and when going overhead they seem to simply growl an octave lower but don't appear to lose any airspeed.

I say don't 'appear' to because I fully realise that they must do and its more that you don't notice it.

And why must it do 11,000 rpm in the air? My PAW 40 should spin an 11x7 at 9500 and it does that up hill and down dale without variance (that I can detect anyway!)

Oh and Ash, I know that diesels are just about dead in NZ due to the fact that ether is impossible to get over there but weather and altitude (especially altitude) can be compensated for very easily by use of the adjustable compression.

Flying at 1500 feet? Use a larger diameter prop in the thin air to get the thrust back, drop the comp to suit and away you go. The South Africans did this quite regularly when competitions were held all over the country.
The amount of ignition improver can be lowered on hot days but this really relates to racing diesels and 1.5% IPN should be good for all conditions.

The only real drama is heat related fuel expansion that makes timing the run a real biatch, that and you will need to heat the engine up before finding a good run setting.

Talk soon, Chris.

ash · « **Reply #20 on:** February 08, 2011, 06:23:59 PM »

Quote from: Chris Wilson on February 08, 2011, 03:23:54 PM

Oh and Ash, I know that diesels are just about dead in NZ due to the fact that ether is impossible to get over there but weather and altitude (especially altitude) can be compensated for very easily by use of the adjustable compression.

Flying at 1500 feet? Use a larger diameter prop in the thin air to get the thrust back, drop the comp to suit and away you go. The South Africans did this quite regularly when competitions were held all over the country.
The amount of ignition improver can be lowered on hot days but this really relates to racing diesels and 1.5% IPN should be good for all conditions.

I was just wondering about whether you need several test flights to get those prop/comp/fuel adjustments right before embarking on an official flight. Is a diesel going to suffer from not having the right setting due to lack of availble practice time on the day of a competition. On the other hand, glows often need the exact same adjustments, so I suppose it is all the same thing.

But as you say, diesel is a tougher game to play here, so I'm never going to put it to the test myself anyway... if only for the amount of oil on the wing!

Chris Wilson · « **Reply #21 on:** February 08, 2011, 07:19:01 PM »

Quote from: ash on February 08, 2011, 06:23:59 PM

I was just wondering about whether you need several test flights to get those prop/comp/fuel adjustments right before embarking on an official flight. Is a diesel going to suffer from not having the right setting due to lack of availble practice time on the day of a competition. On the other hand, glows often need the exact same adjustments, so I suppose it is all the same thing.

But as you say, diesel is a tougher game to play here, so I'm never going to put it to the test myself anyway... if only for the amount of oil on the wing!

Its the compression that gets the fiddling here mate and that is usually looked at after warming the engine up to operating temperature firstly and that takes care of the engine load caused by whatever prop that you might use.

A diesels comp screw seems to equate to a glow's needle valve in regards to care and feeding and with a diesel's needle valve you could just about epoxy in place once a good run setting is found. The thing to watch out for is the engine going 'hard' in the air or over compressing.

But this is supposed to be about engine systems that work or don't work in the wind, and from that aspect I like the big diesels.
They don't wind up with a tail wind.
And they don't slow down in a head wind as much as other forms of I.C. engines due to their massive torque and flat power curves.

But they of course do have disadvantages that are probably outside of this topic.

Cheers.