FINALLY! AN OS Big-Big block!

[PiErow]

So when is it supposed to be out?

 

[cvec7]

Not sure, the guy didn't say...me and a few other people kinda doubt him since he doesn't seem very professional....

 

[Da Hellion]

Os 18

After shelling two RD Logics engines both of which had less then ten tanks this weekend (now I know why they discontinued them ) I had a OS 18 so I put it in my 1/10 car And I got to tell ya WOW this Engine is very impressive . I really have never thought much about OS do to they wheren't really power orientated But that must have changed my friend was running the legal 12 OS and it rocked too OOOOOKKKK now this talk about horse power I have built quite a few engine dynos.and after all my tests and calculations a .12 engine is not capable of producing 1 full horse power It just does not have the torque and I'm talking all .12s I would love someone to prove me wrong on this but so far no one has. The reason for the exaggerated HP is one motor comp didin't tell the turth boosting more then 1 HP and the rest had to follow

 

[Plaidfish]

Suposedly if you can eliminate the wasted fuel from the exhaust, ron parris claimed you should be able to produce close to 5hp from a .12......these engines actually only run around 20% of their efficiency potential.....pretty crazy specs....

 

[Da Hellion]

Suposedly if you can eliminate the wasted fuel from the exhaust, ron parris claimed you should be able to produce close to 5hp from a .12......these engines actually only run around 20% of their efficiency potential.....pretty crazy specs....

Mr. Parris would be wrong if that's what he said . Again size counts here a 12 can not produce the torque to achive a standardized horse power and you can elimanate the waste gas it's called a 4 stroke but once again by doing that (adding valves cam ect) the engine will lose power because size size size

 

[Plaidfish]

those are numbers based on engineering calcs....I know those are never absolute answers so I won't argue the point...but it does lend the numbers of 1HP to be feasable....by changing the porting I'm sure you can get the numbers but you would be sacrificing something else, probably sleeve integrity......you build engine Dynos? that's pretty cool.....what's involved in that and can it be made easily or do you need a NASA machine shop to do it?

 

[greenwing7]

Mr. Parris would be wrong if that's what he said . Again size counts here a 12 can not produce the torque to achive a standardized horse power and you can elimanate the waste gas it's called a 4 stroke but once again by doing that (adding valves cam ect) the engine will lose power because size size size

I think what he is referring to is that if the engines were 100% efficient in their chemical reactions, like human body is, and no heat was produced as a "wasted" byproduct, then you could get that kind of power. but because the engines are not 100% efficient, you get lots less :shrug:

oh and I think that some dynos use different sized props to test their power, but I have no idea how they work

 

[Plaidfish]

^^^ Yep, what he said.....
so what's involved in the Dyno build man...spill it...inquiring minds NEED to know...or we will hunt you down and kill you......lol...

 

[Da Hellion]

Dyno or die!!!

^^^ Yep, what he said.....
so what's involved in the Dyno build man...spill it...inquiring minds NEED to know...or we will hunt you down and kill you......lol...

OK but could you please make it quick and painless? LOL I did a big wright up on Dynos a while back and I'll dig it up for you. Can you build your own Dyno cheap? It depends but there other ways to help you .Home built Dynos can be dangerous to use do to the counter weight wheel spinning at such High RPMs It needs to be ballenced and it's very difficult to do and that's just the macanical part of it . I did come up with a way to see how my engine mods where doing that anyone can do and I will show you how to do this . One thing to keep in mind is that a dyno even the best ones built can only give you a idea of what your engine can produce power wise. there are just to many variables involved IE corrected H/P and Torque readings because of altitude! ANNNNYWAY heres what I came up with to take the place of a real dyno. There are a lot of ways to do this .You just have to figure a way to load the engine and measure it and do it consistently. If you take a electric motor and hook a volt meter to it and spin it by hand it will produce voltage. so what I did was using a belt and pulleys I hooked a electric motor to my nitro motor when the Nitro motor was running it was producing voltage now you have a way of seeing what your engine can produce and a way of recording the tests BUT you need a way of putting a load on it. I have to go to the Lab but I will get back and show you how to do this with pictures and all I promise

 

[niggle]

OK but could you please make it quick and painless? LOL I did a big wright up on Dynos a while back and I'll dig it up for you. Can you build your own Dyno cheap? It depends but there other ways to help you .Home built Dynos can be dangerous to use do to the counter weight wheel spinning at such High RPMs It needs to be ballenced and it's very difficult to do and that's just the macanical part of it . I did come up with a way to see how my engine mods where doing that anyone can do and I will show you how to do this . One thing to keep in mind is that a dyno even the best ones built can only give you a idea of what your engine can produce power wise. there are just to many variables involved IE corrected H/P and Torque readings because of altitude! ANNNNYWAY heres what I came up with to take the place of a real dyno. There are a lot of ways to do this .You just have to figure a way to load the engine and measure it and do it consistently. If you take a electric motor and hook a volt meter to it and spin it by hand it will produce voltage. so what I did was using a belt and pulleys I hooked a electric motor to my nitro motor when the Nitro motor was running it was producing voltage now you have a way of seeing what your engine can produce and a way of recording the tests BUT you need a way of putting a load on it. I have to go to the Lab but I will get back and show you how to do this with pictures and all I promise

Using a dynamo with a resistive load to measure the engine torque is a similar to the principles used by eddy-current dynamometers in rolling roads.

The problem with this type of dyno is that you need to keep the engine speed constant whilst you dial in an increasing load; when the engine speed can't be maintained and drops off you have reached peak torque and if you know the engine speed at which this occurred then you can calculate (horse) power. Unless you can determine the efficiency of the dynamo and the heat lost in the resistive load then it is very difficult to get an accurate estimate of the power produced by the engine under test.

The beauty of the inertia dyno is that it produces a reasonably accurate measurement of the torque curve from a single power run from idle through to maximum RPM; you can see how modifications to the engine affect not only peak torque but more importantly the torque produced at low- and mid-range engine speeds. The torque is calculated directly from the size and mass of the flywheel and the rate of change of the flywheel speed. The only significant losses that you need to account for are frictional losses in the bearings and a reasonable estimate of this can be calculated by monitoring the flywheel deceleration on the run-down.

 

[Da Hellion]

where did this come from

The beauty of the inertia dyno is that it produces a reasonably accurate measurement of the torque curve from a single power run from idle through to maximum RPM; you can see how modifications to the engine affect not only peak torque but more importantly the torque produced at low- and mid-range engine speeds. The torque is calculated directly from the size and mass of the flywheel and the rate of change of the flywheel speed. The only significant losses that you need to account for are frictional losses in the bearings and a reasonable estimate of this can be calculated by monitoring the flywheel deceleration on the run-down. [/QUOTE] So small things like piston/and sleeve expansion don't count huh? and power is NOT calculated on deceleration. Also there is a lot more frictional losses then just the bearings

 

[niggle]

So small things like piston/and sleeve expansion don't count huh? and power is NOT calculated on deceleration. Also there is a lot more frictional losses then just the bearings

Not sure where you are coming from with regard to piston/sleeve expansion, perhaps you could elaborate?

Please go back and re-read my post. I stated that frictional losses (of the inertia dyno) could be determined by measuring the deceleration of the flywheel on run-down, not that power of the engine could be calculated during deceleration.

What other significant losses are there on a simple inertia dyno running in two bearings?

 

[seajj2]

The only part I do not like about these engines is that when you race the highest you can go is a .28.

 

[Da Hellion]

hmmmmmmmm

I just dont understand the way you worded it or copied it . Measure flywheel on deceleration for friction loss IE watch the RPM drop? Ya got me I dont see how this would benafit. When I think of frictional losses that to me means power lost by friction which has to be considerd for example it's not just two bearing surfices .One bearing aloan has many contact points causing friction . A Nitro engine having 3 moving parts is semi true but break it down and the bearing itself has many moving parts. And there are many "significant" power loses in a simple 2 stroke . IE Metal will expand when heated and contract when its cold and different alloys have different expanding rates now how many different alloys are used in a simple 2 stroke. I have seen the Dyno you are talking about and one of mine is similar to it but your getting up into the $2000.range OK enough about that The reason I'm here is to show you a cheap way to help you see if your engine mods worked or went backwards Please let me do that first then I will answer all the Dyno questions that I am capable of answering and also ask myself could my spelling get any worse? gezzzzzzzzzz

 

[Plaidfish]

DH I have access to a full Machine shop, so making precise parts isn't too much of an issue.....I'm trying to make a new Break-in stand right now but if I can add to that at some point and have it act as a Dyno I'd love to....the initial design is using an old chassis from a OFNA buggy and going to mount it permanantly to a starter box...if this initial design does not lend itself to being part of a dyno, please let me know more before I go down the wrong road early on in the game...

 

[niggle]

I just dont understand the way you worded it or copied it . Measure flywheel on deceleration for friction loss IE watch the RPM drop? Ya got me I dont see how this would benafit. When I think of frictional losses that to me means power lost by friction which has to be considerd for example it's not just two bearing surfices .One bearing aloan has many contact points causing friction . A Nitro engine having 3 moving parts is semi true but break it down and the bearing itself has many moving parts. And there are many "significant" power loses in a simple 2 stroke . IE Metal will expand when heated and contract when its cold and different alloys have different expanding rates now how many different alloys are used in a simple 2 stroke. I have seen the Dyno you are talking about and one of mine is similar to it but your getting up into the $2000.range OK enough about that The reason I'm here is to show you a cheap way to help you see if your engine mods worked or went backwards Please let me do that first then I will answer all the Dyno questions that I am capable of answering and also ask myself could my spelling get any worse? gezzzzzzzzzz

OK, bear with me on this one and hopefully we'll hit some common ground. I make no apologies if this get's a bit technical but you can only dumb-down this kinda stuff before it becomes pointless trying to explain.

First of all, forget where the losses occur. Frictional or other losses inside the engine itself do not matter as we are purely interested in determining the torque/power available at the flywheel, not the theoretical efficiency of the engine. If you make modifications to reduce the internal friction of the engine (e.g. conrod windage) then this will become apparent when the engine is run on the dyno by virtue of the fact that the engine is making more power at the flywheel.

Frictional losses in the dyno will be calculated on run-down and will be used to correct the calcuations of the engine's torque/power as measured. We don't need to care why/where these losses occur; we only care that we can measure them.

The torque and losses are calculated from the acceleration and deceleration of a flywheel of known mass. We use the basic f=ma and moments of inertia formulae to do this.

At its simplest the intertia dyno is simply a heavy flyhweel on a shaft supported by a bearing at each end of the shaft. You need a spur gear at one end of the shaft where the engine's clutch pinion engages and a slotted or toothed wheel at the other end of the shaft for the tacho/speed sensor. This is cheap and easy to make if you have access to machining tools.

In addition you also need a speed sensor/pickup with some electronics to interface it to a PC, a PC and some software. The speed sensor and electronics are cheap, everyone has a PC (they are a cheap commodity anyway) and the software is free if you write it yourself.

The software performs three important tasks; it monitors the changing speed of the dyno shaft (acceleration and deceleration) and then calculates the torque and power of the engine from the measured acceleration and known values such as the mass of the flywheel and the reduction gear ratio. Finally, the software plots pretty graphs showing the measured torque and power curves.

If you can do all the work yourself then you can build yourself a working inertia dyno for much less than the price of a new engine, otherwise you're gonna have to pay someone to do all the work and you could easily spend more than $2000 (Software Engineers' time ain't cheap, you know!)

(BTW, I didn't copy any of this, it is all original work based on accepted mechanical theory.)

Finally, the simplest dyno of all is a fixed, marked distance on a slight uphill incline and a stopwatch. Place your car at the start of the marked distance and start the clock accelerate in a straight line to the end of the marked distance. Stop the clock when the car completes the distance. Repeat this after modifying your engine and compare the timings. If the car is getting quicker then your modifications are working.

 

[Da Hellion]

entertaining

I did a post in another site on aerodynamics once and this same thing happend I'll get some one who reads my post then bolts to a site reads a few paragraphs then bolts back and tries to have a debate with me. Guys I have been doing this kind of work for over 30 years (old fart) Do I consider myself to be a expert on dynos ??? My answer would be no. I use them quite a bit and I know how they work and what to expect from them. They are a tool to aid you when searching for more power and that's it It's not rocket sicence and they aren't perfect. They can be expencive so a little over kill for a normal RC racer . When I use a Dyno I'm more intrested in the torque readings then over all H/P . Moving on Do NOT try to suck me in a debate I'm Old ,tierd and I bite! OK heres a way of building a crude dyno not really a Dyno but like a Dyno it will help you see your progress on modifing your engine . First you should know a fuel burning engine will pass it's peak power before it reaches it's max. RPM range Example if your modifacation gave you more top end (higher RPMs) does not necesisarley mean you gained more power you might even have lost some by reducing Torque . This is where you need some type of load on the engine to give you a more acurete reading plus with out it you can damage the engine being tested. Next engine temps play a big roll in determating power! Acording to are friend MR Niggle we can forget this part but I think Ill just forget him! speeking of which once again I spent more time debating then explaining and it's 3 in the morn . Tomorrow I will post pics and finish this post. Mr Niggle if you dont like this info then don't read it and I dont think you are going to sell any Intertia dynos in here you sound like a commercial and Plaid iI did make one using a starter box once I'll dig up the pics tomarrow

 

[Plaidfish]

DH, cool....I'd like to see it....niggle, where do you calculate the moment of inertia...I remember how to do the simple calc for like overhang but that is static.....what's th ecalc for the FW moment of inertia....do you pick a line to the center and use that as the fulcrum (spelling)....your inertia dyno sound pretty nifty...maybe can incorporate both designs into one dyno (meaning my starter box breakin and the dyno)....it's been a while since I did any real equations so bear w/ me on my ignorance.....I get to do valve CVs and Kv load calcs all day now...no brainer stuff i made a spreadsheet for.....I do have access to pulsed readers and other nifty gadgets I should be able to build one of these from parts laying around in the shop here at work....would be a neat toy to have...and maybe build a few for others too.....

and niggle I couldn't find the site on the 2-stroke engine exhausts....my IT guy wipes the cookies and stuff out every week......

 

[cvec7]

MAX-30VG
These have been developed expressly for the Monster Trucks and Truggies.

Three versions are available. 30VG(P) is a standard engine with back plate,while 30VG(P)-X is equipped with recoil starter. 30VG(P) SR is designed to utilize rear adaptor of the original SAVAGE S-25 engine to accept the ROTO START.

Specifications: MAX-30VG(P)

 

[Plaidfish]

NICE....any word on pricing yet?.....Cvec are you buckin for Mayhems job?