OhD

Hi Dave,

I agree with your conclusion but I'm trying to get my head around the statement that geared systems have more torque and if so how that affects driving the prop system. Are you referring to the popular systems we use? It would seem that two systems driving the same prop at the same rpm would require the same torque. Or is there a difference in accelerating the prop or props?
I'm still trying to learn.

Jim O

Zeeb

My Feedback: (41)

Umm... not Dave but perhaps I can answer your question; gears increase torque where they decrease HP. It's a physics deal....

OhD

Hi Zeeb,

I think you meant to say decrease RPM. You surely don't want to lose power going through a gear train and most are pretty efficient. By the way you can gear up and down, so you could increase RPM and have less torque available.

Let's say I had a Neu with a gearbox and a Plettenburg without and they both had the same power output at 6500 rpm wouldn't they have the same torque? I think Dave is getting at some other effect but I'm not sure what.

Jim O

DaveL322

Hi Jim,

I think from a narrative perspective, "we" have come to use phrases like "more torque" in imprecise ways

My intent was to convey that a geared system generally has peak torque available over a broader RPM range (when compared to direct drive) and a geared contra system has a broader torque range than a geared single prop system. So, the contra has "more torque" when considering the full range of throttle. In practice, when transitioning from horizontal flight to a climb, the airspeed lost (given constant throttle position) is the least with a contra, and the most with direct drive. And with the larger surface area in the prop disk of the contra (and the taller gearing), the braking effects are also greater, so the end result is less throttle work is required to fly constant speed.

OhD

It would be interesting to see a speed/torque curve for our "power units". I assumed that both direct drive and geared have the same linear curve from max torque at zero rpm to no torque at max rpm. I was trying to make a case in my mind that the geared motor would spool up faster as the load at the motor output (gear box input) is much lower than the direct drive. I don't know how to quantify that but it probably is not significant. The contra is another case. It is geared for lower rpm and more torque and thus can swing larger props that are no doubt more efficient. Another advantage is the torque on the airframe is reduced by the gear ratio, by about a factor of ten.

Have you seen the videos of the guy with what looks like a helicopter head for variable pitch and vector control? That could really be interesting.

Best Regards, Jim

EHFAI

Jim

Yes, the geared system will spool up faster than direct drive. Direct drive is sorta like driving a car in high gear, accels are smooth and easy to control but uphill speed may sag. Geared systems are similar to driving a car in 2nd gear, quick / powerful accels but harder to manage speed smoothly. The geared system in pattern takes more finesse on the throttle. From watching others fly contra systems I'd judge them to be somewhere in the middle.

Jason Arnold

Anyone care to guess who this Custom Scheme Allure is for?

OhD

I don't know. I agree that a higher gear ratio will give you more torque out and that is why the contra can throw larger props, but at a lower rpm. And yes that makes it feel more like the car in second gear. Maybe it is impossible to have a direct drive system and a geared system that have identical torque-speed curves and that is why we perceive the geared system has more torque. Where is Chad? How does the Plettenbuerg torque-speed curve compare to a geared Neu?

Jim O

EHFAI

Gears multiply torque at the expense of speed. What we're really concerned with is thrust. Direct drive systems generally turn more rpm than geared systems, with the contra defining the low rpm level. With properly sized props, each can deliver the power of the motor to meet our requirements. It would be interesting to measure the performance of each system in the same airplane, yet each has characteristics that appeal to folks differently. Nice to have choices.

rgreen24

My Feedback: (6)

Chip Hyde for post #357

can773

My Feedback: (1)

Hi Jim

I don't know how it compares to the Neu, since I haven't used one. However, the Pletty contra, compared to the Advance....is hard to compare. The RPM range of the single prop is wider, so the model accelerates quite different when compared to the contra. I electronically slow down the throttle in the radio anyway because all the motors spool too fast, so from my perspective as the pilot I can't see any spool time difference. I think when either gear drive or outrunner or direct drive inrunner are operating at cruise RPM, the time to spool to full throttle is virtually instantaneous anyway, probably much faster than anyone would actually move the throttle stick since we try to fly smooth

I am a bit lucky in that I have one Acuracy with the Advance, and one with the contra, so I can compare easily. The Advance clearly has more high speed potential, but the contra has better braking (even than the 3b), and more thrust. I think the closest you can get with a 2 blade is a 22x12 single prop, but you would be slower with that prop than the higher pitch contra.

Chad

DaveL322

Way back in 2006....I had a pair of electric Prestige planes....one with Hacker A60-20S direct drive outrunner, and the other with a geared Neu....both spinning the same props at 7500 - 8000 RPM. Weight of the systems were nearly the same. The Neu clearly had a broader torque curve and responded faster to throttle inputs (accelerating or decelerating), and this is exactly what all the electric gurus (Bob Boucher, Sean Plummer, Shawn Palmer) I spoke with the year or two before told me I would find. The general consensus was that at a given power level, a direct drive motor would need to be about 20% heavier than a geared setup (motor and gearbox) to have equivalent throttle response (acceleration, broad torque curve), and through 2007-8, I found that to be pretty close to accurate after running several other Neu motors and several A60-S (short, ~21 ounces) and A60-M (medium, ~25 ounces) direct drive outrunners (all in the Prestiges).

Current day, the Plett Advance and Hacker Q80-S are substantially improved in terms of torque curve and acceleration, but, they still fall short of a geared Neu (single prop) or Neu Contra. The Q80-XS while still having very good top end power, is noticeably slower to accelerate than the Q80-S. Granted, I have not owned all the motors, or flown them all in the same planes, but I have enough experience with them to feel comfortable making these conclusions.

One of the biggest benefits of a geared system (single prop or Contra) is the mechanical drag of the system. When the throttle is reduced, there is no spool down time....in a downline, the RPM does not drastly increase as with a direct drive setup. At the exit of downline (absent using the ESC brake), the RPM of a direct drive system will be very high, and the bottom 20, 30, 40% of the throttle is a "dead zone" and will essentially do nothing until the airspeed of the plane and the RPM of the motor has decayed. With a geared system, the RPM does not increase as much and the dead zone at the bottom of the throttle is minimal (if any). Adding the ESC brake into the mix substantially narrows the gap between direct drive and geared, but, the geared system is still more honest/true/linear/natural in terms of consistent throttle response at all attitudes and airspeeds.

Brenners Contra on 9.89 gears with 22x22 props is FAST (with 1513 Neu), and the throttle reponse and braking are still good. The only other setup I've come across that will match it for top end is a bigger Neu (1515) running a 20.5x14.5. Of course with the lower pitch props and bigger gears, the Contra will also fly very slowly.

Sorry for contributing to the hijacking of the Allure thread . But...I think this does relate to an idea / scenario Bryan has stated a number of times - planes fly better when they are being "pulled" as opposed to coasting. Geared systems don't spool up as much, and as such, spend very little (if any time) coasting.

Jason Arnold

You get the cigar Rgreen24!

AC has now got his Allure flying and by all reports he's a very happy camper.



A friend in Hong Kong has just received his Ralph Schweizer CRS for his Allure. Looks like a nice bit of kit. Kevin will be using the all new Hacker C54 with this CRS. Apparently, the Hacker C54 is suitable for the Brenner CRS too.



Cheers,
Jason.

Jason Arnold

Hey Guys,

Bryan and Brett have put together a great video on the WC Allure here: http://youtu.be/u1BuGSTbVVo

There is also a video of Brett flying F15 here: http://youtu.be/_DyqMjOFOUE

But wait, there's more... Bryan has now got Chips model on the work bench...


Cheers,
Jason.

rgreen24

My Feedback: (6)

Awesome video. That's how you get people excited about your products. Great job Bryan and Brett.

Jason Arnold

Hi Guys,

CK Aero has received the first half of their shipment from the factory and the other half is being shipped next week! They will be shipping out to Customers in the next few days after Bryan inspects and Sorts through each of the models.

CK Aero will have 6 models unspoken for and available for sale in August/September when the new order arrives!

Cheers,
Jason.

Jet Katt

I was very fortunate to be able to fly the Contra Allure, last October at the Cajun Nationals. I was extremely impressed with Bryan's latest design. The Allure flew effortlessly and things I was used to doing with my Episode, I found I did not have to do with the Allure. It just flew effortlessly. For the past couple of years, I have been very happy with my Episode(s), but the flight characteristics of the Allure are truly amazing. I advanced up this season from Intermediate to Advanced and had tentatively planned to make an Essence my next project, always looking for an excellent design that would give me an edge, because I love the the BJ Craft planes, and this is in no means a shun on BJ Craft, because BJ puts out excellent Pattern aircraft. But after a very long and careful consideration, i.e., flying the Allure, seeing the U.S. team version in person and watching how the Allure handled in Brett's very capable hands in Baton Rouge, recently, and watching my buddy/coach Scott McHarg take a convincing victory in Masters, at the recent Space City Contest, in Houston, while battling with some of our Districts very capable Masters flyers, in a very tight contest, along with the fact that Bryan has worked with me in the past, and he is as close as a phone call or text, and always willing to assist.

Very recently, Bryan called me and we had a very good discussion on these sort of issues and I'm very proud and happy that I made the decision to go with the Allure. Thanks to Bryan, I'll be receiving the #001 Signature Version Allure and I can't wait to get it. Bryan offers something that we usually don't get from other manufacturers, the ability to closely inspect and fly his design, along with the ability of dealing directly with Bryan should the need arise. That added touch gives one the feeling of confidence in making the Allure the Pattern plane of choice. Guys, if you have never flown an Allure, let me suggest that you attempt to do so. As the Quicken Loan commercial goes, "Truly built to Amaze", the same is true for the Allure.

smcharg

My Feedback: (1)

Bryan sent a few pictures of my new Allure to me. I'll be using a 3-blade Falcon and a Neu / Castle Phoenix Edge HV80. The plane came in at 2320g including the landing gear from the factory. I expect this plane to be flying under 4800g with light batteries.

I want to mimic the Contra Allure prototype that I have without the expense of the Contra unit. I think the 3-blade prop will be great on this plane. This will give me two Allures that I can be very proud of. We should have this one in the air shortly.

Jet Katt

Very nice Scott!! Cudos to Jan on her creative genius for that paint scheme.
Not only does the Allure look great, it flies the sequences as good as it looks, taking much of the workload off of the pilot making him\her look
good.

AC Glenn

My Feedback: (2)

Hey Guys,


Just kinda getting around to writing this up but have been meaning to get this out but with prep for the Nats its been a little hetic.

First I want to thank Tommy Goldsten for building my Allure for me and getting it out the door to me pretty quickly along with Bryan Hebert for all his setup work.
Now that I have had some real time with the airplane I can give a honest opinion of the airplane and its flight qualities.
My setup is as follows:

Scorpion F3A motor
Castle Creations Edge HV Lite 85
Falcon 21.5 X 13 prop
Optipower 10s 4700 along with Power Unlimited 10's 5400
Futaba 7008 Rx
Futaba BLS 171 Rudder
Futaba BLS 173 Elevators (2)
Futaba BLS 551 Ailerons (2)
OptiPower 2s 800mah Rx pack

Total RTF weight is 4960 with 1200 gram packs (OptiPower)

Right now I have about 180 Flights on the airplane and must say I'm quite impressed with the performance of the airplane. Running Bryans setup incidence and CG wise the airplane is a very stable airplane in all aspects. The only mix I'm currently running is a throttle to elevator mix for downlines. Knife Edge authority is pretty impressive as I have found working more and more on unknown manuvers. Many of you that have seen me fly know that I fly at a more upbeat pace. I have found that rather I fly the Allure fast or slow that the airplane really locks in on a line and will do whatever you tell it to do. The airplane is really a point and go aircraft.The snaps are very predictable along with the spins. I have done a variety of snaps with it from 3/4 snaps to 2 and half snaps and found that hitting them are absolutely no problem at all. Overall I'm very pleased with the airplane and really looking forward to the nats next week. I will have a video up within a week of the airplane flying P-15, F-15 and Unknown 2 from last years nats. Once those are live online I will post the link for everyone to view.

Dean Pappas

Hi All,
I got a chance to take part in a pre-NATs tunep with Dave Lockhart and his Dad a few Saturdays ago, and I must report that it is a pleasure to see a modern F3A design that does not lack yaw stabilty.
The Allure behaves properly even with the added destabilizing effect of the Contra drive. Well done, Bryan! The mind-blowing knife edge power ain't half bad either ...
all the best,
Dean Pappas

Jet Katt

Hey A.C., I see you, man!

Your Allure is tight, looking good…same color scheme as your Visa, easy to see. I know you flew the contra version last year at the Cajun Nats. Now that you have 180 plus flights on yours, which version do you like best…Contra or single prop electric? How's the power compare with the Scorpion versus the NEU powered contra? I’d like to see you fly at the Nationals, but unfortunately, we won’t make it to Muncie this year. Stay focused and do your thing, I'll be watching from afar.

Are you planning on coming to the Cajun Nats again this year? If so, I’ll see you there.

BTW, tell Albert that I said “Hello”.

Jason Arnold

Well, that was the best days flying I've had for a long time. Put nine flights in on the Allure six of which were with 22" props. Because the model had been flown for so long with 20" props the difference was stark! The gear ratio was left the same at 9.89:1 and the lowest consumption for a P15 schedule flown big was 2601mA. I should never have doubted others claiming this sort of efficiency! These figures are achievable even in the wind. Overall, the model now flys a bit slower but surprisingly doesn't get all waffly. I found that no more than half to two thirds throttle was needed as well. I think the bigger props even improved the horizontal rolling manoeuvres. The three of six in opposite seemed noticeably easier.

I was asked about my throttle curve elsewhere so a picture is attached. The way I adjust my end points is probably a little different to most whereby I do it by ear. :-)


Cheers,
Jason.

Jason Arnold

It's still early days but the Allure currently fills the top three spots at the U.S. Nationals in FAI class. The order is AC Glenn, Chip Hyde and Dave Lockart. Good luck guys!

Cheers,
Jason.

Photo courtesey of Adam Mendonca.

Jet Katt

The Allure finished in the top three places in the 2015 FAI Finals at the Nationals in Muncie!!!

I was out practicing yesterday when Bryan texted the scores to me, and then I realized that I had a message on my cell phone from my buddy Glen Shepherd, telling me that AC Glenn had won the FAI finals. I was not able to make it to the Nats this year but I'm always very excited during Nats time.

Congratulations to the top 8 pilots who made the FAI Finals and a special congratulations to AC Glenn, 2015 FAI Nats Champion, and our own NSRCA District 6 Mark Hunt, who was the 2014 Nats Masters Champion and 2014 NSRCA District 6 FAI Champion, and this year placing 5th in the FAI Finals. I spoke with Bryan on the phone yesterday, it had not really soaked in yet, as to what historic event had taken place....His Allure finishing in the top 3 positions in the 2015 FAI Nationals.

This just goes to show that Bryan has really outdone himself with his new Allure design, quite possibly making it the most winningest and most popular Pattern plane on the planet. Congratulation also to Mr. Bryan Hebert. As I stated in post #367, 'If you looking for a Pattern plane that will definitely give you the edge and you haven't flown one yet, you definitely need to fly and buy an Allure.

I'd also like to congratulate our own NSRCA District 6 Vice President, Chuck Hochhalter for placing 7th in Masters, and, 2015 National Champ, Jeff Worsham for his 1st place victory and Nick Marson for his 3rd place victory in Intermediate.

Good Flying Guys!!