bpryor

My Feedback: (45)

finnz, are you messing with us?

If not, boy are you a hard sell. Rocket means rocket. You'll have unlimited vertical at around 1/2 throttle and YES, it will hover at 1/4-1/3 throttle....no doubt!

Bill

mikerc

My Feedback: (11)

Anyone else what to chime in????? Richard thanks for the advice on Taurus. You must be a spokesman for the company. Change that pilot thing in your Extra 330 it lookes bad. Dick I was wondering if I use aluminum stand off for my ZDZ how long would I make them to keep the carb outside of the firewall? Thanks you.

mikerc

My Feedback: (11)

Using the stock firewall that is. Thanks

JBH

My Feedback: (1)

Hi finnz!

Yup... in the 12-14 lbs range the ZDZ-40 will allow you to park a plane on the prop and then pull out with power. I'm all for using it on most any 1/4 scale plane. But, I would build it light... like I did my Kangke CAP (you can check that out on my website). Cut the covering off the bottom of the plane and get the dremel out. Then use all the lightest gear you can. I had an OS 1.60fx in the Kangke CAP at exactly 11 lbs. I'm shooting for exactly 12 lbs with the ZDZ-40. Wing loading should be good and power should be awesome. :-)

Don't be too hard on Taurus' #1 spokesperson regarding that pilot figure... I think it's a self portrait or something. :-)

mikerc

My Feedback: (11)

Thanks Joe. I like your website btw. Nice work. I want to see more videos of the cap though.

JBH

My Feedback: (1)

Hi finnz!

Sold the H9 33% Cappy almost a month ago. I do have one video of it on tape that I'd still like to convert and post. My friend Mike held the camera and told me to TR over his head. I told him he was crazy but he insisted. The video is crazy cool! :-)

The next videos will be of the AW 33% Edge... probably harrier rolls down on the deck. And, the H9 Taylorcraft... side slip'n in a foot high. That is the plan anyway... at this point neither one of them is even built. :-)

rmh

Bill -I should have said " a dyno -used by others will really tell you little you need"
A dyno used by me for my own work -would be fun-no doubt.
Again-for propellor fact finding-and that is what it is really all about, You can do the job faster -more accurately with a set of calibrated load paddles.
There prsently are not any made for our size needs --at least I do not know of any-
They were once available fo small glo engines -carved from aluminum blanks -a friend still has a full set-from --Germany (strange)
anyway-these tell you the real world -instantly.
When I setup an engine for aerobatics-one of the steps -actually the final step -is to run the engine very slowly up thru the entire rpm band -with my eyes closed -and listen to the power build.
I can tell if the increase is linear and or if the mixture is shifting at various points.
No magic here- just a learned art -lots of guys have learnt (sp) it.
A few props -the type found to best at pulling -or speed -under known airframe loads -are needed.
This is another learned thing.
So for those who really like to tear and compare -scratch and sniff-lick and taste-whatever -You too can make a test setup!
Get props you have found to be a good performance standard -for your own interests.
mark em -set em aside -
run your engine on em -record the info - make exhaust changes - fuel changes -whatever - one at a time - and record the info!
When someone tells your their belchfire 40 will turn a carbon fibre zippy 20 x10 at 10000 rpm-don't be impressed - try the belchfire on props that do the job you want done.
That's dynoMITE testing.

rmh

finnz- mounting the ZDZ40 -in the 1.20 Cap is not just a matter of adding standoffs and bolting it all togather.
Check with RCS- they have pics on doing this - it involves a cutout in the firewall and four little 1/4 " thick plywood discs as standoffs -
Seriously
If this is not a job you are comfortable with -
Or have hobby tools to do the job. there are other engine choices which you may prefer.

bpryor

My Feedback: (45)

finnz wrote:

>>Richard thanks for the advice on Taurus. You must be a spokesman for the company.

Did you mean me (Bill) finnz? If so, like I've said before, it's my first one, but I was so impressed I felt compelled to spread the word. However you take my opinions about the Taurus, all I can tell you is that they're sincere, and backed up with 29 years of modeling, 39 years of 2-stroke racing, and ownership of many, many gas R/C engines.

>>Change that pilot thing in your Extra 330 it lookes bad.

If you're talking about my pilot, all I can say is at least I have one, which 99% of DP Extra's don't, and I bet nobody else's weighs under an ounce. As far as the looks of the pilot goes, I can't do much about that, but I'm kinda partial to it.

JBH wrote:

>>Don't be too hard on Taurus' #1 spokesperson

#2

>>regarding that pilot figure... I think it's a self portrait or something. :-)

Yep, kinda sick, huh?...but actually I just think you guys are envious.

Bill

bpryor

My Feedback: (45)

Hi Dick,

>>Again-for propellor fact finding-and that is what it is really all about, You can do the job faster -more accurately with a set of calibrated load paddles.

Those sound very useful, I wish someone was making sets of those paddles for our engines. Sounds like a good business for someone.


Bill

mikerc

My Feedback: (11)

Im just poking fun Bill. Thanks for the advice.

f308gtsi

My Feedback: (1)

How about the ZDZ40 in a Yellow Aircraft Spitfire ???

The span is 88" and it will weigh approximately 20-24 pounds when finished. The recommended engines are Moki 1.8, G-38, and ST3000.

Is this enough engine ? Will it sceam down the flightline ? Will it have good vertical power to perform loops and climb outs without lagging ? I don't need to hang it on the prop and hover, but I would like it to climb off the deck with authority. I really would like it to scream in a flat out low level pass to terrify the "hover" crowd. LOL

thanks for the input guys.

rmh

The recommended engines are way too small -in my book -but the ZDZ 60-80 would do a spendacular job!

DESERT RATT

My Feedback: (7)

OK BOYS, I LIKE I USUALLY DO ON THESE SITES I STARTED A SOMEWHAT OF A BATTLE (JUST ASK MY VIETNAM BUDDIES ON OUR WEB PAGE)
I didn't mean to cause a problem, but I'm getting the information off of it that I "needed-wanted"
NOW TO WHOEVER IS GIVING "BILL" A BAD TIME ABOUT HIS PILOT, LEAVE HIM ALONE HE HAS BEEN A "GREAT HELP AND INFO TO ME THAT HE ISN'T EVEN AWARE OF" THANK YOU BILL!

DICK, are you the DICK HANSON I READ ABOUT IN THE AIRPLANE MAGS PAGES?
I agree with DICK on many points that he's brought in the general catagory of engine POWER... THERE IS NO "COMMON DENOMINATER" in these smaller engines as we have in the multi-cylinder hot rod things. IE: a proven dyno. capable of using an established measurement accepted by all in the industry.
I've been in the hotrod building hobby and some serious stuff (used to work on TOM SNEVA'S roundy rounder before he became a house hold word up in SPOKANE WASH.)
I have been into this hobby for a while, and have too many of these BIG BOYS TOYS, but I'm new to this GAS thing. I have two friends that are trying them out and I'm not impressed "so far" but they are running ZENOA'S AND BRISON'S (no I'm not bad mouthing either one of these manufactures but I'm not impressed with the "power to weight".
They are running these engines in the H-9 540 and the MIDWEST 330 78 inch wingspan.
I'm used to seeing the MOKI 210 pulling these birds straight up. I live in a remote area of NEVADA. 65 miles west of LAS VEGAS and I do not have the time to make the trips to VEGAS to hook up with the gas boys there. so I appreciate the help and information you guys are sharing here on this board!!!


The advertised weightof the GUADROTECH ULTIMATE is 10 to 11 lbs. with a 120 SAITTO. wingspan of 58.25" and wing area of 1182.5 sq."

DICK,
THANK YOU FOR YOUR HELP! YOU'RE A WEALTH OF INFORMATION, INFO. THAT I "WILL" UTILIZE.. I APPRECIATE YOUR SHARING IT WITH THE REST OF US!!!!!!!

RON in NEVADA (PAHRUMP)

OH YEA, here's another one...
WHICH HAS MORE POWER, YS 140L OR THE SAITTO 180 4S??

Diablo-RCU

My Feedback: (1)

Well I can't let this go without putting in my 2 cents on the dyno biz. I'm in the DH camp. I see little practical use to the dyno with our application. The engine that turns your favorite prop the fastest is the one with the most power - that's it. Our engines don't need a fat torque curve like a Harley, because as they accelerate the prop from low rpm, the load is very low. Broad and flat torque curves buy you nothing, despite the 3W ads to the contrary. The only thing that counts is the HP in the rpm range where you want to run your particular prop. The HP/ rpm plot for ANY prop (in air) is an exponential plot. The HP / rpm plot for any of our engines is a curve that will always be above the prop HP / rpm curve until they intersect at full throttle (high rpm).

The other point is that dynamometers (like props) are not all created equal. Dyno A may say 10 HP with engine X. Dyno B may say 11 HP with engine X. If you test 2 engines on the same dyno under the same conditions (or normalize the outputs for air density and temp etc.) then at the end you will know which engine is more powerful. If you test the same 2 engines with the identical prop and measure rpm, then you also know which engine is more powerful. All that other stuff (torque and HP at low rpm) that the dyno will measure is of no real value to how much thrust the engine can generate.

bpryor

My Feedback: (45)

First Diablo, what you state about two engines on two different dynos is a given. Of course, comparing HP/Torque numbers between multiple engines is only valuable, as you stated, when tested on the same dyno.

>>If you test the same 2 engines with the identical prop and measure rpm, then you also know which engine is more powerful.

Yes, you know which one has the most peak HP or Torque...which is it BTW. Is that really all that matters? I think not. I'll go with 3W on this one.

Bill

Diablo-RCU

My Feedback: (1)

Bill:
Can you explain why you think that torque matters for an engine that drives a prop? The aeronautical engineering power texts that I've read don't agree. Look up some prop load/rpm data for yourself. Compare the shape of the curve to any engine you can think of. Low end torque matters for wheel driven vehicles but not for props. Unless you are going to prop your engine for 3,000 rpm max, then the power it makes at 3,000 rpm is not very meaningful. An engine with a dip in its torque curve at 3,000 rpm just means that the throttle will be open a little more to maintain a steady 3,000 rpm when compared to an engine with a bump in its torque curve at 3,000 rpm.

bpryor

My Feedback: (45)

Hi Diablo,

>>Can you explain why you think that torque matters for an engine that drives a prop?

Huh? Of course torque matters, it's not peak HP driving the prop at 6500 RPM on our engines, it's torque. I believe peak horsepower for most of our engines is in the 8-9000RPM region. Peak torque is in the 6000 RPM band. I'm not sure where the 3000RPM number came from that you're talking about, but I certainly never suggested that's the important RPM band for our motors.

Bill

rmh

Maybe to clarify a little bit--
Prop load is a very non linear function-typically.
Why? because most fixed pitch props only really work well at a particular rpm.
A generalization would be that the load is zero at an idle and max at the rpm where the engine can no longer turn it faster.
However- this max point may Not /may be the best rpm for THAT prop's best efficiency!
Here things get into the cut and try realm.
In thick air - a narrow blade prop may be a good match for the model being optomized.
But in thin air the same prop is not very good.
Most models -flying at lower speeds -(aerobatic types)work better with props which produce high thrust at low speeds.
That is a over simplification -of course.
Very light pogo sticks /lawn darts etc., work great with small fast revving props-but they fly in a pretty low speed range and the thrust is gradual in it's build up -easier to adjust .
a good jet engine would really be great here- but that's another story.
Bottom line - for our stuff -flying competition aerobatics-an engine which pulls a wide /long blade at lower rpm's generally works the best.
kinda like a helicopter.

bpryor

My Feedback: (45)

DESERT RATT(Ron),

First, I'm glad you found something I've posted useful. Thanks for the good comments.

I think Dick missed your question about being the one in the magazine. He says it's not him, even though it could easily be him, and I guess he has posed for a few centerfolds in his time.

Thanks for defending my pilot, he appreciates it. He's been struggling with anorexia and has a hard time dealing with critisism.

I really don't mind the kidding, it's being done in good spirit. Besides, I've gotten so many compliments on the pilot at the fields I've been to that I can take some jabs at it too. It's definitely not for everyone. I doubt we'll be seeing any like it at the scale masters...but it is light!

Bill

Diablo-RCU

My Feedback: (1)

Hello Bill:
Torque and horsepower is kind of like the chicken and the egg. Usually when someone says an engine is torquey, they mean it has a torque curve that peaks at low rpm and falls off rapidly - like a Harley. If they say an engine lacks torque, they usually mean that the torque curve peaks at higher rpm. The max horsepower an engine develops always occurs at rpm higher than the torque maximum. The maximum thrust for any engine is developed at maximum horsepower, not maximum torque. This is true if you can match the correct prop to the engine so that it turns at the correct rpm and the efficiency is not changed with rpm (which isn't usually the case). It's also true that if the max HP is developed at a very high rpm (e.g. 16,000 rpm), then you may not be able to use that HP unless you can prop the engine for 16,000 rpm. If we prop our gas engines in the 6,000-7,000 rpm range, then the manufacturers better have ported the engine to develop the most power (not torque) in this range.

Getting back to the original problem. If engine A turns the 26x10 prop at 6500 rpm, and engine B turns the identical prop at 6400 rpm, then A has more horsepower (and more torque since they are mathematically related) at 6500 rpm.

If I slap a 30x10 prop on both engines, I might find that engine A turns 4500 rpm and engine B now turns 4700 rpm. How is this possible? Engine B has more torque and horsepower at 4700 rpm.

Most people would call engne B the torquier motor because it has more low rpm torque. Does it matter for a practical sized prop? No.

By switching a few props, you can determine what kind of useful power the engine can produce. Pick a practical prop for the plane/engine combo and compare with the other engine. The biggest rpm with the useful prop always wins the torque and horsepower contest.

Texas 3D

My Feedback: (16)

Hi,
does anyone would have the phone # of QUADROTECH ? I seem not to be able to lock on to their website anymore.
I purchased a Ultimate from them a couple of weeks ago, and it arrived damaged and send it back, but have not heard from them.
Thanks

Aerowerks

What would be the best gas engine to go on the 1/4 hanger 9 cap 232 at the most reasonale. I was told a 2.4 1st place engine and also a zdz but im not sure

Michael

NSSHERLOCK

Get your soldering outfit warmed up, as apparently you will have to solder up a hole in the ZDZ engines choke plate before you can draw fuel for prime. While you are at it get ready to change out or modify the throttle arm and the choke arm to make them useful for the average modeler. You might look for a decent muffler also unless you intend to fly with earplugs. If these engines are made only to fly model planes, why can't they put carbs on them that don't require re-engineering?

Bob Pastorello

My Feedback: (198)

He's right! On the 40, the chokeplate hole is too large. On my newest (just a couple runs old), I soldered it completely closed. Have to watch for too much prime, but since it will pop and give it's choke run, it's not a problem. Re the carb; I think that designing an effective and efficient gas carb from the ground up must be a heckuva job, or else the OTHER gas model boys would have done it. Fact is; for these size motors, carbs aren't better than the Walbro/Bing/Tillotson. Re the throttle linkage - I guess the choice to redesign that and add more to the front end cost of manf. the engine v.s. letting the user customize it for their needs was made....we have to know what/how we want the throttle setup.