ajcoholic

My Feedback: (10)

This is just an open question to the modelers here who either like or dislike not just my work, but engine reviews in the mags in general.

I have tried over the past 4+ years working for Fly RC magazine, to develop a true, real world style review in which I get an engine and treat it just like I do with my own purchased engines.

That is to say, I break it in correctly as per the manufacturer's directions and suggestions for props/fuel/plugs/etc. I run a number of props and fuels to make sure the engine is not only broken in but well run enough to provide me with an honest display of its performance. Also dissassemble and inspect the internals and how its made.

Then, I actually put the engine in a plane and fly it enough to get to know the characteristics and plus's and minus's.

Keeping in mind the fact that I have only a month to do the work, and since I have a life (like a full time job, a wife, etc) I cant spend 200 hours testing an individual engine. As it stands I spend roughtly 20 to 40 hours PER ENGINE on the review. Thats a solid work week of spare time.

I honestly want to try and provide my freinds and other modelers with the best review I can so I am asking what do YOU want to see iun a review??

Thanks for your time,
Andrew

HighPlains

My Feedback: (1)

Well you could farm out some of the work. Since I'm a degree'd engineer and now a farmer....

Your reviews look pretty good in print. I don't care for prop selection sometimes, but that may be partly because I think the manufacturers are show very heavy props as a marketing ploy. (This engine must be stronger than that one because the props are bigger.)

Case in point, your latest review on the OS 75 AX, the lightest load is a 13x7 and you only get 10,160 rpm and that is the highest number. Yet OS (via Tower) gives peak power at 15K. I would have liked to see 12-6, 12-7, 13-5, 13-6 sizes instead of 14x10 or 15x6.

It might also be great to know dB reading at WOT.

w8ye

My Feedback: (16)

The figures given by the manufacturers are not always accurate nor practical.

High Plains, From an engineering point of view, it usually works out well for us to prop for a static rpm half way between the torque peak and horsepower peak.

You will find that the small prop it would take to turn 15,000 would not get the plane off the ground.

Andy, you are doing a good job

Hobbsy

My Feedback: (102)

You do an excellent job AJ, I tend to prop engines for good flight power rather than some imaginary, impractical HP number. Running an engine at 15.500 rpm just makes extra noise, wastes fuel and beats up the plane needlessly.

HighPlains

My Feedback: (1)

Gee, this isn't my first dance either.

NikolayTT

I have not been reading those reviews but I believe they are very uselful. Is there any www-page where one can
get at least the titles and the abstracts of those reviews ?

What I would like to see is Question I would like to answer this way: - We discussed many times recently over RCU about
how useful is the Resonance Pipe for Engines, and many say it is very uselful but nobody told ANY serious measurements
versus open exhaust. Even some people say for example Macs pipes give about 25% power boos while Macs pipes themselves
give numbers which recalculated give not more than 8% boost. Thus, here is a Proposal if you like to get many people
refering to your article: - If you get some good and popular engines, take their Gas diagram and then for couple of
them with big difference in the gas diagram place Resonance tube, tune it and tell the RPMs versus the RPMs on open
exhaust. As good candidates I would suggest OS-160FX and MVVS-26cc glow; that will make a big bang on the readers
minds - I am wandering in fact if someone has not done that yet, any recollections ?

Cheers,
Nick

ajcoholic

My Feedback: (10)

OK, this is something I am interested in discussing. Generally (and more based on my own modeling experiences) I pick prop choices based on both the recomendations and my own preferences. I generally go a little bigger in pitch and diam and a little smaller. I didnt think to run the AX75 on smaller props as I figured most of these will be flying in sport and scale airframes - not in speed ships. But I will try and enlarge the prop test range from now on. Thanks for the reply!

By the way, I always give a db reading in the flight testing section - in front, back and off to each side running WOT on grass (our field). I use my radio shcack digital noise meter.

Thanks, AJC

PS hobbsy and w8we - thanks guys!

HighPlains

My Feedback: (1)

I've only owned and flown one .75 engine in the last 37 years of RC flying. A ST S75 ring engine that spent about 400 flights on an Acrostar bipe. I got the best performance on a 13x5 Rev-up prop turning 12,000 on the ground.

The performance of almost any airplane is directly related to the power. Not only is the top speed related to engine power, so is the rate of climb. While any prop selection is a compromise, moving up the rpm range is how to improve the power to weight ratio of a model. I like to use large diameter and slightly lower pitch to achieve the best total performance, usually limited by when I can no longer fly in knife edge without losing altitude.

I missed your db reading in the text. I would tend to believe that they would change with rpm and prop used.

RaceCity

Andrew, I think it's wonderful that you posted such an inquiry, as it shows that you're genuinely interested in the quality of your work.

I subscribe to the magazine, and have for the past several years. I generally consider it to be more of a catalog, and less of a source of information. I do however make it a point to visit your engine reviews as one of the first orders of business when new magazine arrives each month. The FIRST order of business of course is to shake out all 450+ "subscription cards" from the mag. Gads!

Given that you have deadlines, and are limited by the clock as to how much time you can spend with a product....I'm not sure what more I could ask. Still...at the end of it all I come away knowing little more about the product than had I never even looked at the review.

OK. So the "XYZ .61" comes in a brightly colored box. The engine and muffler are packed in individual plastic bags, etc, etc, etc.

We learn that it turns a prop I'd never use, at "X" rpm. It idles "superbly", and so on and so forth. I've read this same basic line 10,000 times over the years in various publications, and it wasn't always so at the field!

Given that "3D" and "Scale Aerobatics" represent a sizeable segment of the IC engine applications out there.....how about a little about the THROTTLING of an engine? How does this thing do with a prop suitable for that? Would you trust your plane to this thing 6" off the ground? Lots of engines idle, or go fast. Occasionally...you can get both. To get a smoothly functioning whole however without undue tinkering, modification, etc is noteworthy while this very sort of information is strangely absent not only in FLYRC, but in just about any other magazine I've ever seen as well. This suggests to me that whoever reviewed this thing likes to fly at WFO in big circles, and the motor could have hideous performance shortcomings yet come out smelling like roses.

Long story short, perhaps if the review engine were flown in a variety of applications by persons who "specialize" in that sort of flying you could provide a more comprehensive overview of it's true capabilities. I say specialize because a "great transition" to one guy is a stuttering disaster to another. Is that possible?

Thanks for giving us the opportunity to tell you what we think. You asked.....

I do appreciate your work, and can only imagine the challenges you must face ever month.

Thanks again, and keep up the good work.

DarZeelon

Nick,


Power relates to RPM through cubic value.

I.e. to spin a prop twice as fast you need 2 cubed, or 8 times the original horsepower.

Air resistance makes the effort four times as great, since drag is a function of speed squared and this effort must be exerted over twice the distance per time unit.


So, a 25% horsepower boost (quite typical from a good, muffled tuned-pipe) will result in an 8% RPM boost, or 7.722% to be more accurate.

How did you make your recalculation?

FoamyVictim

This is the best suggestion yet! Give it to several people in distinctly different applications. That way, the 3D guys hear what they want, and the scale, or sport guys hear about the props and airframes that they plan to use...

ajcoholic

My Feedback: (10)

Race city -

I am surprised about a few comments, mainly the "props you will never use" - is that due to the brand, or the sizes? I always try and select a wide range of props to test run. I chose Zingers mainly due to the fact I buy all my own props and I spent about $300 on test props. I cannot test all brands due to cost.

As for the comment regarding throttling, well, my background in modeling is quite varied, but I love to fly fun fly/3D style planes and also have been doing IMAC for years now. I do appreciate good throttling and I ALLWAYS comment both in the bench testiing segment, and more importantly in the test flying portion how the engine responded not only during "flying around" but throughout allphases of aerobatics including loops, rolls, snaps and spins, and all combinations of these. I chose my test aircarft based upon ease of getting many engines mounted and tested - I have from time to time used one of my IMAC or fun fly planes to test engines but generally I cannot. However I do wring out the engines VERY hard, as my friends will attest to. I certainly do not just take off and fly around.

I do not acceot anything less from a test engine than I do from my own engines. I will not praise an engine for idling if it sucks. Or, say the transition is excellent, if it sputtered and coughed through the midrange no matter what settings. But the information you suggest I put in IS already there! I sometimes wonder if anyone really reads my reviews word for word??

Most engines I review are not "use specific". Take the OS 75 AX for example. It would be at home in any sport plane, scale aircraft, fun fly plane, smaller IMAC plane, etc. It is not IMO designed for speed. Test flying the engine in my 4*60 gave me enough information to know how the engine behaved, coupled with the bench testing - and to make a descision on the overall performance.

Long story short, if I write that the engine "idles superbly" then, well, it did. Remember I back up ALL my words with performance figures. If you want RPM numbers they are there. to test idle for instance, which I do ONLY after the break in and running has happened (it is so unfair to test a brand new engine for idle) I let the engine sit at the lowest reliable idle I can achieve (after a warm up run for a minute) and let it sit for a few minutes. Then I quickly open the carb fully and see what happens. Is that not fair?

ANyhow, I am sorry you find my reviews worthless. I appreciate your time to post though, thanks.

ANdrew

PS lots of my engines both idle extremely well, and go fast. I dont think I am "lucky" either, having many many engines that just seem to run great (not only the majority of test engines, but all my purchased engines as well). I have had a few I had to work on to get right, but most of the engines I run perform extremely well. I do think experience, understanding, proper treatment, etc has more to do with an engine's behavior than just the brand name. I can show you LOTS of guys who can take a perfectly running OS, Saito, Webra, etc engine and within minutes bugger it up simply because the think they know more than they do, and they do now want to learn properly how to set up and run a model engine. Sorry to say it, but its very true in this hobby.

ajcoholic

My Feedback: (10)

That would be ideal - however totally impractical from a standpoint of sdoing a review for a model magazine.

I can see in the future if I can vary the model's I test fly engines with somewhat. If you want to see more 3D and fun fly type, then I can do that.

Andrew

WMB

My Feedback: (1)

Some of the automotive mags keep a car for a long term impression. After the initial review, you could give a real world viewpoint after having "lived" with a certain engine for a period of months or flights. It takes me some time to really get to know a new engine or airplane.

Keep up the good work! MikeB

FoamyVictim

I see, just thought it might give a more "rounded" review. In some of the RC Car mags I read, they bring several drivers to test a new chassis. That way, it doesn't seem so one sided. I have no doubts about your opinions or ability to wring out the motors, but it's always a little more reasuring to hear reports from more than one person. You make an excelent point about a ding dong being able to buger up a great motor and call foul on the brand/model. I see this happen at the track all too often. If I get the chance I help the guy, rather than say... "Must be because it's Brand X..." I will, and we keep another racer...

RaceCity

Andrew I think I inadvertently conveyed some negativity in my earlier post regarding your work, and if so...that was not the intent.

I give up.

Cyclic Hardover

My Feedback: (3)

Funny man!

Cyclic Hardover

My Feedback: (3)

I agree on the variety of applications thus pushing what the manual recommends also. Take a simple TT 46pro. On a trainer and an 10-11inch prop, it putts around the sky doing what it should. General all around good engine. Or install it in a Shrike as i did with a 9/7 apc prop and nearly 17,000rpms with an Ultrathrust muffler, is a real screamer.

All I ever see is an engine reviewd in some Fourstar or whatever. Put these engines in some decent planes.


Need to tell it like it is. Shoot ,I do! Our hobby is flooded with arfs. From the high dollar down to the "pos." They all fly good but a healthy percentage are made up of junk. ABS fuselage? Cmon now. So old guy walks by and farts within 10 ft of these things will melt the boom right over and you should bring these cases up.

What about the "deals" out in the world. I have a few world models planes. Nice Arfs and had them several years. i found this POS on ebay i was going to get as a fly around beater. When I got it and loked it over, I would guess it came from a WM factory and they through a cheap name on it. Beautiful thing and turned out to be one of my better flying planes. Still have no "beater."

I still think the best reviews are right here on the RCU. We tell it like it is and pull no punches.

HighPlains

My Feedback: (1)

Why?

DarZeelon

In magazines funded mostly by commercial advertisements, it would be very difficult for an engine review editor to write exactly what he thinks about the engine... unless it is all positive, that is...

Even if the engine was purchased at full street-price from the LHS, the US/UK/whichever dealer for the engine's manufacturer is paying for ads in that magazine...

If the review contradict that ad; and this goes for equipment reviews, models reviews and R/C system reviews too, the magazine could ki$$ it goodbye...


RCM magazine suffered its demise about a year ago... Could it be a result of some of its writers trying to tell the truth?

w8ye

My Feedback: (16)

There are a lot of variables in the use of model engines. I don't see how a test in any particular type plane is going to please everyone?

It's sorta like the argument of two stroke - four stroke.

It all comes down to the two stroke has more all out power, no doubt about it. But is that everything that is all important to everyone?

The low speed torque characteristics of a big four stroke intrigues many 3D people but not all of them?

It is all into what a guy can make work for himself and what he thinks is best?

Ed_Moorman

My Feedback: (1)

I hate to disagree with you, Dar, but I'd say that RCM started its downhill spiral when Don Dewey, the founder & owner died.

HighPlains

My Feedback: (1)

Dewey, Cunningham, Willard, Kidd, all gone.

DarZeelon

No disagreement here, Ed.

I was just 'thinking out loud' of what could have caused the fall of this magazine.


Many things could have contributed to it and its fall meant there was no money left to continue...

blw

My Feedback: (3)

Andrew reviews engines in his own manner of testing them out. Clarence Lee had his own way of doing the same job. Neither reviewer has the time or money to be as totally comprehensive as suggested here. Keep in mind that what interests some people may not appeal to others.

Readers need to make decisions based upon the material given by the reviewers, and any other things they learn elsewhere. No review is going to be the end-all-source for our decisions. That would be impossible, and probably boring to most readers when a review like that would run 10-20 pages. I guess that a review could do that, but we would probably only have 2 or 3 engines tested in a year of publication.