togatoga

My Feedback: (42)

I have the tgy52. I measured the piston diameter as 45mm, similar to the CRRC pro 50.Stroke for both engines is states as 31mm. Therefore going by swept volume as the measure for capacity we get 3.414(pi) x 22.5x22.5x31 = approx 53.6cc.TGY calls it a 52cc and CRRC calls it a 50cc. Who's right? Are my calcs wrong?

For the DL50 the bore is 43mm and stroke is 35mm. Going by the same formula we get 3.414x21.5x21.5x35= approx 55.2cc.Is that why the DL50 is more powerful?
The zenoah g20EI has a bore of 32mm and stroke of 25mm which gives 3.414x 16x16x25=approx 21.8cc
The zenoah g26 is 34mmx28mm which gives approx. 27.6cc.
Are the bore and stroke figures given rounded up to the nearest mm and thats the reason for the anomaly?

tomyrcmodels

Hi togatoga

I'm not agree with your caculation result . base on one number you use are not correct . the pi are 3.14159. not 3.414. so the result you got are different with my.
TGY 52 . 45mm bore and 31mm stroke . capacity are about 2.25cm* 2.25cm*3.14159(pi)*3.1cm=49.3CC. it's close to 50CC .not 52CC. so if TGY52 are use 33mm stroke . the capacity will be 52.48cc.

for the rest of engine like DL. 43mm bore . 35mm stroke . it's 50.8cc

togatoga

My Feedback: (42)

Oops Tommy, you are right! Thanks,got that wrong. 22/7 gives 3.1428.However,that being said, its really baffling how the numbers sometimes don't tally with claimed capacity at times.

Ram Jet

Do we take into consideration cumbustion chamber volume with the piston at TDC, measure the stroke when the piston fully covers the tranfer and exhaust port or the intake and exhaust valves are closed simutaniously? I believe that a manufacturer/engineer disigns an engine that is .572666987 c.i. and marketing says it's a .60.[&o]

Bill

soarrich

My Feedback: (98)

Sometimes it's just marketing. If you where to bring out a new 80.2cc and called it an 80 it would just be another 80cc engine, but using the same size motor and you called it a 81 it would be unique. If I said 327, 409, 426, 454 would I have to tell you who made them?

gkamysz

My Feedback: (19)

No, we don't take those things into account when figuring displacement. The only things to consider is bore(technically not piston diameter) and stroke. Nothing else matters.

I've seen published bore and stroke figures rounded. Otherwise, it's just a marketing thing. The OS FS-20 is actually .215 or something.

victorzamora

I don't know about you guys, but I'd much rather buy a "DA50" or "ZDZ-80" for my 50cc and 80cc planes, respectively, than buy a DA-50.2340987321549287542 or a ZDZ-80.3438219743 (I just made up those numbers, fyi).

In the olden days (apparently), there were no engines called .46's. My dad talks about his .45's...now they're .46's. I'd bet it's a difference of them being .454 and .455. Oh, and if you want to be really specific with pi, it's:

3.1415926535 8979323846 2643383279 5028841971 6939937510 5820974944 5923078164 0628620899 8628034825 3421170679 8214808651 3282306647 0938446095 5058223172 5359408128 4811174502 8410270193 8521105559 6446229489 5493038196 4428810975 6659334461 2847564823 3786783165 2712019091 4564856692 3460348610 4543266482 1339360726 0249141273 7245870066 0631558817 4881520920 9628292540 9171536436 7892590360 0113305305 4882046652 1384146951 9415116094 3305727036 5759591953 0921861173 8193261179 3105118548 0744623799 6274956735 1885752724 8912279381 8301194912 9833673362 4406566430 8602139494 6395224737 1907021798 6094370277 0539217176 2931767523 8467481846 7669405132 0005681271 4526356082 7785771342 7577896091 7363717872 1468440901 2249534301 4654958537 1050792279 6892589235 4201995611 2129021960 8640344181 5981362977 4771309960 5187072113 4999999837 2978049951 0597317328 1609631859 5024459455 3469083026 4252230825 3344685035 2619311881 7101000313 7838752886 5875332083 8142061717 7669147303 5982534904 2875546873 1159562863 8823537875 9375195778 1857780532 1712268066 1300192787 6611195909 2164201989

to 1000 digits. I was going to post it to 200million digits, but figured it'd get REALLY boring.

soarrich

My Feedback: (98)

Can I get that in Cherry?

victorzamora

You just add a 6 on the end of it for cherry, a 3 for pecan, a 2 for pumpkin, a 1 for apple, a 4 for sweet potato, a 7 for lemon merengue and a 5 for chocolate pi

karolh

1,000 is quite enough thank you, and I would like mine in strawberry ... my favourite flavour.

Karol

BTerry

My Feedback: (8)

MMMM, pie!

Pi is "about 3". Just ask any engineer

victorzamora

As an engineering student, my final exam is based solely on the term "-ish" Please don't think I'm kidding.

jack1933

My Feedback: (2)

Uh 426 I remember a 427,, think the 426 was an off brand forud or something, found on the road dead, correct me if im wrong, please.

JNorton

My Feedback: (2)

Can you say 426 Hemi???

jack1933

My Feedback: (2)

426 hemi there I said it what does a mopar have to do with the engines sorich refered to? I assumed he was refering to G. M. engines.

soarrich

My Feedback: (98)

426 hemi probably THE most famous number.