FINALLY! AN OS Big-Big block!

[cvec7]

No, no price yet..but I'm estimating under $300, although that really isn't saying much...

.....Cvec are you buckin for Mayhems job?

Not quite sure what you mean there...

 

[Plaidfish]

He is the official RCNT writer....he's usually posting new products all the time....haven't seen any thing from him in a while though.......

 

[niggle]

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

The personal character assassination I can live with (to be honest I couldn't give a sh*t for your opinions), but please don't misquote me - stick to the facts.

Apologies for breaking your stride, I'm looking forward to your pictures and completed post with great interest.

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......

The formula you need is the moment of inertia of a solid cylinder, specifically the inertia of a cylinder rotating around a central axis. Think of a flywheel as a flat cylinder. The formula is:

I = (MR^2) / 2

where M is the mass of the flywheel and R is the radius of the flywheel.

Contrary to DH's speculation, I have no commercial interests here and certainly no dynos for sale. I can't help you with the machining side of things but if you need any (free) help with the electronics and/or software side of things then please feel free to PM me.

 

[Da Hellion]

Lets rock!!!

I decided this would be kind of fun so what the hell. I find it ironic that you seam to elaborate on accuracy but you push inertia style Dynos which as far as Dynos go they are the least accurate which would explain why very few people use them any more. The problem with them is the fixed value for the load + HP=(mass)*(acceleration)*(distance traveled/ /time of test). from H/P,Torque can be figured by the RPMs (Torque=H/P*oooo/RPM) pulling that almighty H/P figure . Based on the value set on the load that H/P number can be very missleading And if some RC engine builders are using this type of set up that would explain the exaggerated horse power they claim. Is this not true ? can you dispute this? I'm all ears fire away !!!!!! Don't forget now as you stated stick to the facts If you claim a inertia dyno is superior to a load dyno show me. This auta be good

 

[Da Hellion]

OK Mr. Niggle This wasn't ment to be a personal attack on your character. The main reason I joined this site was to share my love of this hobby even thowe I do it for a living. I get a lot of emails asking me to explain questions they have about RC Cars & Trucks. I wish I had the time to answer all of them but I don't so I refer them to a RC site such as this one (my fav site) That way they can go threw my posts and if I didn't cover there topic chances are someone else did in here When I do have time I enjoy helping people . You seam like a smart guy so I would hope you understand how frusterating it can be when I'm trying to explain a simple way to build a inexpencive dyno then all the sudden some one compleatley blows it way out of perportion then the next thing I know I'm debating that person instead of explaining the subject I set out to! "You make no apologies for making this technical" Do you how that sounds ? It tells me that you are trying to convince people you are smart but you kinda fell short . You said you don't give a poop about my opinions so would you like to debate dynos some more ? LOL now I'm the one who sounds arrogant

 

[Plaidfish]

what do you do for a living w/ RCs?
just curious....
and this debate better stay friendly guys......cause when it comes down to it












I'm smarter than youOUUUU!!
NANNY NANNY BOO BOO

 

[cvec7]

...I'm smarter than youOUUUU!!
NANNY NANNY BOO BOO

...blaming the gov. on this one is very immature and ignorant......

look who's talking...

 

[RatzoRC]

Back to the reason why this thread started.
It will be around $270 when it hits the market.
My friend called his distributor.

 

[Da Hellion]

what i do

what do you do for a living w/ RCs?
just curious....
I Build RC bodies and for right now that's the only thing I sell to the public. I also build parts for two RC companies I have a pretty big facility where I do a lot of testing and also do RC product reviews. I don't right them I just give them the information .Two things I'm working on is building my own Nitro engine and a transmission that adds ratio as needed with no gear changes I go out and get the best bodies in each class then I do testing on them in my wind tunnel (down force & drag) then I compare the data against my bodies then do what I need to them to make mine have faster lap times.This is why I work 7 days a week and have no life . My Harley picked a fight with a car and lost so I have been laid up for a while Bla Bla Bla .If I was out of line in this post I do apologize I just get frustrated sometimes and by looking at this truck body I'm doing you will see why I need to take a brake ! Is this ugly or what? O well back to work












I'm smarter than youOUUUU!! Hell my dog is smarter then me!
NANNY NANNY BOO BOO

I'm smarter than youOUUUU!! Hell my dog is smarter then me!
NANNY NANNY BOO BOO[/QUOTE]

Ya see It's so ugley it wont even post

 

[Plaidfish]

Cvec, Hope you do realize that was a joke, making light of a pissing contest that was arising....
Ratzo, thanks that's a bit more than I was hoping it would be, but maybe I was dreaming......
I want one of these for my truggy now......any word on US release dates?

 

[cvec7]

I hope you realize that what I said was a joke as well...

 

[Plaidfish]

wasn't sure that's why I was posting in a "non-emotional" way.....and besides I never said I wasn't immature...I just said that thought process was... ...you gonna get one of these beastly mills too or am I gonna be the pioneer here?

 

[cvec7]

Nah, I'd like to race the savage, and I think that the OS will be too much power for it, but I dunno....I'll just have to wait and see the price, and how others like it. But so far I think I'm goin w/ the hpi .28 since it is currently the best racing engine for the savage next to the RB 28....

 

[Plaidfish]

If these are under 250 I'm gettin one...If not I'll be getting a Rossi from Rush......I just haave had good experiences w/ OS so I'll give them a try first......

 

[Da Hellion]

Os?

I'm tellen ya man That little TZ.18 suprized the heck outa me ! 5 or 6 years ago I ran a few OS Engines but you had do do heavy mods to them to get any power out of them but they where good engines and very easy to tune. I put a TZ.18 in my car and well....WOW. I think it would be a great engine for a Savage tons of torque and Ill bet it would be faster then that 76 I stuffed in My Savage I'm doing a exsperiment with a Nova Rossi .12 boaring the block to take the OS 18 sleeve & piston. Why am I doing this ? I have no idea!:shrug:

 

[niggle]

> very few people use them anymore.

1:1 engine tuners tend not to use inertia dynos because typically they are interested in holding a steady RPM to optimize fuel and ignition mappings and you need a brake dyno to do this. On a glow engine the carburation and ignition adjustment facilities are so crude it is not worth bothering with a brake dyno.

Rolling road interia dynos are only 95% accurate because the rotating mass of the driveline between the engine and the rolling road (clutch, flywheel an driveshafts) can only be approximated. With an inertia engine dyno, the rotating masses are fixed and known.

> the problem with them is the fixed value for the load

When you dial in a load on a brake dyno to hold a steady RPM the load is also fixed, so what's the difference?

> Torque can be figured by the RPMs (Torque=H/P*oooo/RPM) pulling that almighty H/P figure . Based on the value set on the load that H/P number can be very missleading...

Actually, with nearly all dynos, the torque is measured or calculated directly and HP is then calculated from the torque value and the relevant RPM.

Common sense dictates that if the inertia dyno flywheel mass is very low then the engine is going to pull an unrealistically high RPM and the calculated HP will be impressively high. The solution is to use a flywheel mass that limits the engine speed and acceleration in the same way as the chassis and driveline would if the engine were being used for real.

> If you claim a inertia dyno is superior to a load dyno show me

The best inertia dyno will never be as good as the best brake dyno, that I will concede, but let's put all this back into context:

What was originally proposed was a simple inertia engine dyno as an alternative to a very simple brake dyno based around a DC electric motor being driven as a dynamo. Some kind of variable shunt load will cause the motor/dynamo to generate a braking torque against the glow engine under test and the braking load can be determined by measuring the voltage/current in the shunt.

IMHO, the electric motor brake dyno has too many variables;

• Brush/commutator condition will deteriorate
• Brush spring tension will deteriorate
• Motor efficiency will deteriorate as it heats up
• Shunt resistance will change as it heats up
• Power absorbed in the coupling between the engine under test and the dynamo/motor

All of the above would cause a perceived change in braking load even if the torque of the engine under test did not change, i.e. there is a strong likelihood that a false reading will be obtained.

In addition, unless the efficiency of the motor as a dynamo is known, it is almost impossible to calculate an absolute power output for the engine under test. This is further complicated by the fact that the dynamo's efficiency will vary with speed.

Finally, brake dynoing an air-cooled glow engine is just too damned fiddly, it gets hotter as you dial in more brake load and even if you can hold the speed steady whilst you measure the load, the fuel tank is emptying and leaning out the mixture, making the engine even hotter - the engine's power output is constantly changing.

Personally, I would rather take an inertia dyno that is repeatedly 95% accurate and gives me a torque curve in a matter of seconds over an electric brake dyno that is inherently more difficult to calibrate and requires repeated measurements over a number of different steady engine speeds.

However, if you are telling me that you have found an inexpensive way to circumvent the problems detailed above then I would be very interested in hearing about it, in fact I would positively encourage you to consider producing such a device on a commercial basis.

 

[Plaidfish]

WOW.....can we say I.Q. pissing contest here.....lol....that's some pretty impressive knowledge both you guy sbring to the table....I think we should develop a levitating device and leave RCs to the little people....
seriously I think you guys have cool thoughts on this topic and would hate to see something like this escalate into more than it really is...remember this is fun.....

 

[RatzoRC]

I think you guys have cool thoughts on this topic and would hate to see something like this escalate into more than it really is...remember this is fun.....

I agree.

 

[robriguez]

screw those guys...


FIGHT!!! FIGHT!!! FIGHT!!!




jus kiddign...Damn I wish I paid more attention in math and physics classes so I could follow along a bit closer.

Anyway, i have never gotten my picco .26 to run right in my savage so I am def looking for a replacement. I would assume that such a large engine would require a large(er) pipe as well, no?? If not I have a CVEC, an HPI ribbed, a Standard s25 pipe and some other "racing" pipe i paid like $50 for at my LHS so one of those should work I guess.

 

[Plaidfish]

man you did get confused......lol....whatchutalkinbout willis