matt43

On the subject of speed that is one thing..... BUT why do you want a trainer or cub to go 114??? Why not get like a sundowner or a racer and go 180??? They are designed for a purpose and taking them out of that design area is dangerous!!! Look at controll surface size and hinge gap... A Toledo special going 114 is asking for flutter and a lot of wasted money.... Also the potential to hurt someone depending on WHEN it does come apart!!

rctech2k7

My Feedback: (1)

I fly with specified engine for my aircraft but I also experienced to overweight my scale model which required me to add structural reinforcement and upgraded engine. There are big difference with regards to stall speed and acceleration specially on takeoff at rough runway where part of the load is still handled by the gear which resistance (frictional force) is very dependent to the weight of the aircraft (normal force). I also experienced how easy to fly an aircraft with slightly over power, takeoff acceleration is fast and aborted landing is forgiving where as for lower power engine which I also experienced would take time to spool up and while the ground is coming in fast at the end of runway, drag produce by increasing AOA can only result in lost of airspeed then eventually lift. This is why as much as possible I don't land my aircraft in idle power...

rctech2k7

My Feedback: (1)

These are the reason I think:
-Desired for high Power (P/W) and Thrust (T/W) to Weight ratio
-Unlimited vertical maneuvers
-Slightly independent from the law of inetia
-Semi-free from the law of aerodynamics
-Higher and faster energy output since machinery varies with efficiency
-To be able to save from the penalty of slight aerodynamic mistake

rctech2k7

My Feedback: (1)

If T/W is too much then probably to escape the reality of an airplane...

Seamus OLeprosy

My memories from learning to fly in the late 70's was that nearly all the models I went through were underpowered and on more than a couple of occasions lost a model where more power may have got me out of a tricky situation resulting in a couple of weeks of repairs.
Back then engines were expensive and anything like a OS40 FSR was more than a weeks wages.

Mustang Fever

My Feedback: (2)

I like to play with the tradeoffs: power/weight/speed/handling. Fiddling any one of them too much usually results in one of the others being adversely affected.

My Shrike 40 has an OS 46AX on it with a 10x6 prop. Turns about 15,000 on the ground, which works out to only around 85mph, but over 6 pounds of thrust on a sub 4 pound airplane. It's overpowered by any stretch of the imagination, but the handling is superb and it will fly right out of my hand during an underhanded launch. The wing loading is light enough that it has no bad habits. I chose the engine because it has the best power to weight ratio of any reasonably priced mill, and it's important on the Shrike to keep the nose light, as they want to come out nose heavy.

My TF B-25 ARF has a pair of O.S. 55AXs, versus the 46s called for. I kept the bird as light as possible: no additional scale detailing and fixed landing gear. On our bumpy grass field, it makes a reasonable take off run and performs well, in a scale manner, at 1200 feet above sea level on a 75 deg. day. With 46s, it would be marginal. The torquey 55s also allow me to use good looking 12x6 3 blade props, and the rpm is low enough (10,000 WOT) that she'll fly around a long time on 11 oz of fuel per engine. The 55s are a bit heavier than 46s, and that helps with the C.G. (These things come out tail heavy.)

My TF P-51 .60 ARF flew OK with a 75AX, but I wanted some more punch in the verticals, and it just didn't have the top speed it needed to carry through manuevers. A 95AX turns the same prop (15x8) around 1,000 rpm faster and weighs the same so it didn't affect the C.G. (These build nose heavy.) I really like the way it flies now.

One of the best reasons for overpowering is so that a scale size prop can be turned without overloading the power system. I just repowered my Hangar 9 Sopwith Camel, after many years of flying it on a Magnum 91 2S with a 17x5 wood prop. It flew OK, and with that prop was not what you would call overpowered. The heavy .91 helped with the C.G. as that short Camel nose made it real tail heavy. I went to a Turnigy G60-300 electric motor on a pair of 3000 6S packs mounted way up front in the cowl. Using Markus Muller's ecalc, I chose a 19x10 APC E prop. (20" is scale, but with the tail up for T/O the tips would be in the grass.) It's looks just perfect, and flies so much better I can't believe it. It is definitely overpowered, so I just don't need or use full throttle. I can cruise around forever on only 15 amps, and have plenty of punch for fun when I'm so inclined.

So, to answer the question, overpowering (as compared to the manufacturer's recommendations) can be use to accomplish a number of goals. Now, if you go over to the extreme speed prop planes, you'll find a totally different approach. Them boys is after speed, and they don't care about nuthin else. More power to 'em, but if my Shrike could do 130 mph I don't think I could keep up with it.

tfarmer96

Yes i am! But the planes im over powering are not 60 size.......

I would rather add motor instead of lead.

Mustangman40

My Feedback: (1)

Bob,
be careful, you might get hooked like I did...

I always use to fly close to the recommended engines in my planes and still do on some of them... Then I started tinkering with getting a little more speed.... This best way I can describe it, It's like driving 60mph then coming to a small town where it drops to 30mph.. Holly cow it feels like you are sitting still, you get that feeling like you could walk faster.. It's kind of like that!

I like having the extra power under the hood for when i feel the need to open it up. Other wise a 60 size plane flys like a 60 size plane with a 120 in it, long as you fly at half throttle...

Jimbo

rctech2k7

My Feedback: (1)

That's true but remember we're not flying rocket or helicopter here. I know it require lots of skills but feel free to follow what is design for your aircraft. If your aircraft requires more lift on takeoff, optimize high lift devices and provide enough runway. Aside from safest way to do, it would be more beautiful to see your plane takes to the sky through the purpose of the wings and the energy she earned.

Thisstrangeengine

I have always had more power than needed in most of my aircraft since it will get you out of a bad situation when needed. Now I'm not talking about putting a 1.20 on a .40 size model, I am refering to putting say a .32 on a .25 size model or a .52 on a .40 size. I think alot of planes like a .40 size model are advertised with a .40 being marginal as an example. An old saying goes,"It's better to have it and not need it, than need it and not have it".

AmishWarlord

My Feedback: (5)

So you not going with the called for .60's in your Nosen 310?

TexasAirBoss

My Feedback: (22)

I build mostly scale airplanes these days. I prefer to go small with the engine. It typically leads to a cleaner install. The suprising thing is that going smaller and lighter often results in faster. And if you really like speed, taper and foil the tail feathers. It removes about 1/3 of the material, and thus 1/3 of the weight. And it reduces drag significantly. This will increase speed of an airframe far more than additional power. Remember, the airframe generally determines the top speed. The power generally determines climb performance but has minimum affect on straight and level speed, the airframe determines that. As drag builds up, it requires more and more hosrepower. In the end, a clean airframe is the only way to really go fast. Go to Reno. Look at all of the Casade racers out there. They are limited to engine size. (I forget what the displacement is, but its small.) Those airplanes go like rockets. This is the fastest airplane I own. It is a 7.5lbs Sig bonanza with a OS 50AX. The plans called for a .60 engine. (The kit is from the 1970's, so .60's were gnerally not ported as well as they are today, it was also befor CNC machining and the advent of modern alloys, so a typical .60 had about the power of a modern .46.) But you should see this thing blow past sport ships. ITs pretty funny because its so fat , (yes fat, about 9")!

BTW, those are fixed gear

glydrjocky

An old crusty[>:] crop duster pilot once passed on to me the secrets of his long lived aviation career. He took me under his wing and said "Tony, there are three things in aviation that will do you absolutely NO good."

1. The runway behind you.
2. The altitude above you.
3. and the fuel you left back at the pump.

Perhaps that's as good a reason as any to over power an airplane, you can always throttle back but bending the firewall once the throttle hits the stop isnt gonna get you any more power!

You haven't lived until you've gotten caught in a down draft with a 65 horse Air Knocker Champ at full throttle and had the terrain get closer than you'd like.

Thanks again Reese for those words of advice, I'll never forget them!

Tony Iannucelli

My Feedback: (193)

"SOME IS GOOD, MORE IS BETTER, TOO MUCH IS JUST RIGHT."

willig10

Simply put more power if needed is a good thing. Weight and.balance is another. Also you dont have to fly at full throttle

karolh

Back in the early 90's I built a GP Big Stik 60 and powered it with a stock ST60. Shortly after I switched engines to a ASP. 61 with a Mac's tuned pipe and on the very first flight when the engine came on the pipe the increased performance scared the living daylights out of me, not to mention that it gobbled up the 14 oz. of fuel onboard in no time flat.

Karol

Thisstrangeengine

NOOOO SIR AW, Going with a pair of 1.20 four strokes unless I can find a cheap pair of G-62's LOL

llindsey1965

My Feedback: (-1)

my patty wagstaff is rated 30cc i have a 56 cc everything has been beefed up , verticle is unlimited and no manuver it cannot do , not about speed but the power to get you out of a situation !!!!

rctech2k7

My Feedback: (1)

We should consider large engine based on our requirements and design of an aircraft not by what we wants. A lot of management guys failed on disregarding technical point of view... If within specified range are fine but once we're going outside the border is becoming dangerous. Even if we don't used full power all the time, it creates small fraction of damage caused by maximum stress and deformation. If you want speed, you can find an aircraft with lesser drag, jets are good example, most likely you'll get higher terminal speed and higher efficient aircraft. Most of all it's a high perfomance aircraft that can stand considerable high g maneuvers. If you want more lift at lower airspeed you can add more lift from surface devices. Finding an aircraft that suitable for the purpose, selecting the right airframe for the engine and vise versa I believe is the best choice.

blhollo2

My Feedback: (278)

well for one, its not a trainer airplane or a cub style airplane at all, the thin airfoil wing allows it to be a quick airplane it cuts right through te air. And if you read my post fully i stated its been reinforced to handel the speed and stress which makes it safe to fly. Now when doing 114mph your not yanking it around or throwing the sticks around. Zero flutter when its been REINFORCED and hasnt hurt anyone! over 200+ flights and counting. Just because you can do 114mph doesnt mean you have to..its called power on demand. stick to your Prius lol

rkbruner

You're a member of a Cub Brotherhood, so I'll assume you fly scale. I flew a Twist 60 with an OS 61FX for over 400 flights while I learned basic aerobatics. Simply not enough power for 3D. It now has a 91 on it, and will pull straight up from a hover. That's the beauty of our hobby, and living free. We can chose what we like. I like to watch nice scale planes flown scale, but have no interest in flying them myself. There's a guy in our club who will only fly electric, but he is openly critical of all who don't fly electric. Don't be that guy.

NM2K

My Feedback: (14)

Well, you are right that not just any model makes a good hot rod. At least not without special attention being given to things such as reinforcing the engine mount, wing retention system and hinges. More importantly is how prepared the pilot is to throttle back should things begin to get out of hand.


Ed Cregger

ron a norman

My Feedback: (14)

Overpowered? I like mine with a little extra Zip!! But I always beef up the control hardware to prevent flutter.

ron a norman

My Feedback: (14)

Some more pics

kerwin50

Several 20 cc gas do not have the power of a120 nitro. TThe 20 cc gas equals a 90 nitro unless your talking about a dle 20.