Kmot

My Feedback: (24)

How many pounds of force is there on a piston changing direction 180° at 7000 rpm?

frets24

My Feedback: (15)

That would be a linear mass/velocity equation. I'm sure it's a lot more than we might think possible. Thankfully we're not experiencing rod stretch and piston to head impact problems


Carosel,
The physics are what the physics are. Not intrested in debating the math just sussing out an issue, weighing the data(no pun intended) and trying to determine if there is a reasonable, cost effective and easy solution. I was quite shocked at the force load as well. (By the way...you were right...won't quite fit the ESM FW-190 dimensionally.[&o] May go with the new Zero (thanks for the heads up)or a larger scale 190.)




There is no arguing that these clips seem to be the single most problematic component of an otherwise satisfactory design. I think that as a group we have been able to see some things in a new light, learn some stuff, and involve ourselves in an intresting mechanical mystery. Hopefully we can make some more enlightened decisions based on the fruits of our quest and save some headaches. All great fun when it deals with something we all enjoy anyway.

Tom may have drawn the most logical conclusion here earlier.
1) the stock clips are inferior. They should be replaced. 2) In our repeated tinkering, even quality clips have been over worked causing them to become weakened.
Conclusion: Replace stock clips and in future tinkering make an effort to replace with new clips whenever one is removed.

I won't have an airframe for this one for a while so I'll call the relaced e-clips good for now. I'm going to keep an eye out for any new info before comitting to a ring clip. I do think that they are the most failsafe but balance that with the idea that it maybe overkill and un-necessary.

frets24

My Feedback: (15)

Good insight. Had not thought of that.

Looking forward to nothing other than good news on your future flights!

wherewaldo

hey guys ...I was still losing a cylinder as i idled down ...running very rich....I turned the low idle screw about a 1/4 turn leaner
seems to run better ..but i am still losing the cylinder ..but now when i give it full throttle it re ignites the cylinder how can i give this a permanent fix...
It idles nicely...but it fouls the one plug until i give it full throttle ..but for a few seconds its running on 4 cylinders
any suggestions appreciated
thanks

retransit

My Feedback: (18)

"Tom may have drawn the most logical conclusion here earlier.
1) the stock clips are inferior. They should be replaced. 2) In our repeated tinkering, even quality clips have been over worked causing them to become weakened.
Conclusion: Replace stock clips and in future tinkering make an effort to replace with new clips whenever one is removed."


And thanks to you engine/enginering types for the heads-up. I'm replacing mine before it is installed on a new Fleet.

Bob

Carosel43

i know for sure the forces can be calculated out given the right equasions, bu has anyone mapped the link pin path as they run oval as i recall. In any case the forces will be high, but i just doubt a 1.5 gram clip will have 7lbs pulling on it, if it did then i think they would all be flying off everywhere on all the engines. Os and saito also manage just fine. i think the crappy clips is the real issue

378

My Feedback: (4)

OS And Saito are made to a much higher standard, too. There's a reason the OS 300R5 costs so much more.

Kmot

My Feedback: (24)

Not gonna go there..... such as the O.S. engines liners peeling and the Saito ball bearings crumbling on virtually new engines.....

rockin daddy

My Feedback: (32)

Tom:

Just bought an ASP 400 just like yours. Also have a Saito 325 radial. I am a machinist and would make a new crankpin out of a good high quality piece of heat treated chromemolly steel if I experienced a damaged clip retainer groove. Don't you know a friend that is a machinist? The replacement pin will be as good if not better than the original. Would save you a few $$$ and alot of time.

Best regards,

Charlie

Kmot

My Feedback: (24)

Hi Charlie,

Thanks for the comments.

Well actually, I do have a machinist friend who already made me some trick link pins years ago and I have them installed in my engine now.

Reverend

My Feedback: (3)

Right, sat down last night to assemble the engine. Three minutes later I was done. Wrong E-Clips [:'(]
So the engine is still in parts... [&o]

@Tom: I had printed your table and taken it to the hardware store. It turns out the yellow highlighted ones are the correct ones.

Rev

Carosel43

Yes, os have had issues with liners and bearings. The 200 surpass will do a set of bearings in between 6 and 12 months apparently. as for the LA Series....well, i switched to ASP two strokes because of them, the FP Series was far better. As for saito they do seem to be cutting some corners. The master conrod on my 450r3 for exampleseems tohaveno bush, just the aluminium of the conrod running straight on the pin! My main complaint about saito is the nitro obsession, the vibration (of singles), the high comp ratios, fuel consumptionand their fragility in a crash. There is no doubt however that saito make very powerful engines that are extremely light. OS...I dont know, i just sold my 52 surpass(lovely little thing) and still have my 91 surpass (had a habbit of eating bearings and valve springs in its early life) which is another very dependable engine, but i have heard/seen bad things about the newer engines as they seem to be trying to make them down to a price, not to mention that they are doing electric motors now. That said, people reading this thread may think the ASP 400 is a bad engine with all our problems, but in reality im sure there are many many engines flying without drama

Carosel43

Rev, do you think that by the end of this you can do an F1 Pitstop style 400 rebuild? if not then you should at least be able to do it in your sleep!

Reverend

My Feedback: (3)

yes, goal is a complete assembly in under 30 Seconds.

Kind of funny how much respect and fear about tearing this engine down I had a couple of weks ago. Now its done in 60 Minutes while watching an episode of Top Gear.

I have to back you up on one thing though. Concidering how many of these engines are running, they are actually a great value for the money. Reusing those Clips is something they will fire you for in man carrying aircraft so its my own fault and the fact that my engine has survived TWO of these self inflicted failures actually speaks FOR its toughness.

I love my 400.

Rev

Carosel43

i love my 400...when its bloody working! thats the issue, when its working its great but when its not its never an easy fix.

Now, to actually try and be helpful...

Waldo! your issues with cylinders going out could indeed be mixture related, one thing i wanted to ask was how your throttle response from idle was. If its kinda slow then lean the bottom, if its quite punchy then it could be another issue. Also if its just one cylinder have a check of the valve clearances and glow plug condition of that cylinder, it could be something specific. Also which cylinder is it? for me no1 was always the worst

Kmot

My Feedback: (24)

My apologies Phillip. I only underlined that page to show what was available and at what cost. I later correctly identified the e-clips needed as having a 4mm diameter:

http://www.rcuniverse.com/forum/fb.asp?m=11245989

http://www.rcuniverse.com/forum/fb.asp?m=11246050

booker-RCU

My Feedback: (43)

I've been following this forum with great intrest as I have an ASP 400 that should arrive this week. I'm thinking I'll open up the back and change out the E style clips before running it at all. As I followed the forum it sounded like the best thing to do was replace them with the circle clips but I see the E style being ordered. So which would be best and If it is the circle clips which one would it be?
By the way I've been using McMaster Carr for years and their shipping is fast, the rates low and competive pricing.

Thanks,
Galen

Kmot

My Feedback: (24)

Galen, I would not change the clips out on a new engine. I think you will be okay. However, if you disassemble the engine at some point, then do not re-use the old clips. It seems that is the issue, reusing the old ones. Always install new clips is the new mantra.

booker-RCU

My Feedback: (43)

Tom - Thanks - Sounds like good advice. I also have a EVO -777 that runs excellent. I think I'm becomming addicted to the sound of cyl in a circle!!

Galen

Heli-NuBee

My new ASP 400 radial engine that I ordered from Hobby King arrived last night. If I had seen the pictures from Reverend before I ordered, I may not have purchased this engine. I have both a Saito 200 Radial and a UMS Evolution 7-77 radial engine and I am quite happy with both. I purchased the ASP 400 to put into my CMP 80" Zero. I guess I will just have to open up the engine, replace the rod pin clips and hope for the best before I even run the engine.

Heli-NuBee (Roger the radial rabbit)

Kmot

My Feedback: (24)

I rec'd my clips today from McMaster-Carr. Made in USA so I know they are awesome. Here is one resting on a stock link pin. You can see how much it needs to expand (and get worked) to fit into place. And why we need to replace them instead of reuse them.

Thanks again to the Reverend!

frets24

My Feedback: (15)

Heli-NuBee,
Don't rethink your excitement over your new AR400FS. It's a good engine.

To quote or paraphrase a few of the gurus here: (certainly)...."there are many many engines[ar400's] flying without drama." "...the fact that my engine has survived TWO of these self inflicted failures actually speaks FOR its toughness." and "...It seems that is the issue, reusing the old ones(clips). Always install new clips is the new mantra."


Contrary to what you may be thinking now, after hearing or reading about a problem in the engine, this is a pretty well designed and relatively trouble free piece of equipment. I know it may be intimidating that there's been a lot of discourse on the link pin clip, but this seems to be the only real problem that has been identified over the course of 47 pages and several years on this thread. For my peace of mind, I would (did)change the stock clip; it's easy and inexpensive. Looking at the clip in Tom's post above I can see a real difference from the ones that came stock on mine. The one's I just took off were a straw colored anodized clip with some burrs on the edges. Tom's have a nice black finish and look quite smooth, especially on the edges...no micro fractures waiting to spread.

Put that baby in your Zero and post a couple pics here and post bunches on the 80'' Zero build thread! I'll be on the lookout for it

Welcome aboard from another nubee to the thread.

Reverend

My Feedback: (3)

Tom, sorry, I guess my post sounded wrong. Its not a problem at all, the hardwarestore is just around the corner from the office. I failed to read the posts with the correct rings. My own booboo [&:]

I'm not sure I back you on not changing the clips on a new engine. I spoke to the guy I bought mine from and he told me the first failure (e-clip on Nr. 2 Cyl jumping out) occured about three hours into operation. If I am honest, I am not sure how well that chinese guy or girl is educated in putting in e-clips, theres a lot you can do wrong there, and the fact that there are quite a few of these radials in my vicinity where these non reused clips have jumped out tell me, that there is something fishy with them. I am still not sure if these Clips aren't just too soft.

If you look at the big picture, then this is the most frequent failure on the fs400. I think opening up the factory new engine is a very smart thing to do.

1. You get to know the engine and can check for any obvious factory fault and milling residue.
2. You can check the link pins for cracks
3. You can easily change the E-Clips for quality ones (dont forget to wedge a piece of wood between the link pin and the housing to do so or the pin will definitely find its way into the front housing
4. and if you are really motivated you can change those chinese bearings for really good quality ones
5. It only takes two evenings to do all of the above
6. Its a lot of fun (at least for me)

I think that if you do all this you will not be opening that engine in a long time.

Rev

Reverend

My Feedback: (3)

oh, and fwiw: I sat down and calculated the Force on those clips last night as well.

Using my old physics textbook I figured out about 1,5kg (3.3lb) pulling on that clip @ 7.000rpm

That is still a lot and I think that could be enough to pull a reused clip from the shaft.

As a matter of fact, I am going to figure out a way to test this. I am so happy with my 400 I have purchased another one. Well, its scrap at the moment but I hope to get it up and running next year. With some luck it has the original clips and I can test if they hold the 3.3lb. Should be arriving soon.

Rev

Carosel43

I am very tempted to buy another one from HK myself as most fo the issues i have with mine are due to the poor quality of the old SC engines and the fact that it suffered total mechanical failure (which may or may not have been my fault). the other thing i would say about taking a new engine apart is if you do that the warranty is gone, but i dont know how good HK are with things like that as i have never tried. Also, i dont have another airframe for it at the moment, and i still need to find a home for my saito 450 now i finally have it running better. Anyone got a large aircraft they dont want?

In any case, the 3.3lbs on the clipsounds a little more realistic to me but still means the engines have to be very closely balanced. I know for a fact that we do not balance our engines to that degree so im still uncertain. That said i do not have the time or formule (or the energy required) to 'do the math'. Either way, lower rpm is better for engine life! especially as the engine can be expected to unload by upto 1000rpm in the air. Thats why i aim to run mine at 6600-7400rpm on the ground. I also think i am going to have to bite the bullet and order a new glow driver system, which will be about £80. this makes me sad