4-stroke without a locknut?

4-stroke without a locknut?
View related threads: (in this forum | in all forums)

Logged in as Guest

Users viewing this topic: none

Printable Version

All Forums >> Glow Engines, Gas Engines, Fuel & Mfg Support Forums >> Glow Engines >> 4-stroke without a locknut?

Page: [1] 2 next > >>

Login

Message

<< Older Topic Newer Topic >>

4-stroke without a locknut? - 7/9/2007 9:40:42 PM

RVM

Posts: 1975
Joined: 3/12/2006
From: Sacramento, CA, USA
Status: offline

Anyone flying around without a locknut on their 4-stroke? I've got a spinner that will only fit if I don't use a locknut on my Saito 100. I don't think this engine has backfired on me once, and as far as I know that's the only reason a 4-stroke will throw a prop.

Any experience here? I've never flown a 4-stroke without one before.

_____________________________

There is no substitution for human competition.

RE: 4-stroke without a locknut? - 7/9/2007 9:50:58 PM

Posts: 3741
Joined: 3/30/2003
From: Garland, TX, USA
Status: offline

From everything I've heard, you're fine as long as you keep it rich enough to avoid a backfire.

_____________________________

Regards,
Carrell

(in reply to RVM)

RE: 4-stroke without a locknut? - 7/9/2007 10:08:21 PM

Posts: 1717
Joined: 2/7/2004
From: Bergen, NORWAY
Status: offline

The older 4 stroke engine was without locknut..

_____________________________

Jens Eirik
All landings are just controlled crashes!

(in reply to carrellh)

RE: 4-stroke without a locknut? - 7/9/2007 10:56:16 PM

Posts: 13513
Joined: 3/20/2002
From: San Bernardino County, CA, USA
Status: offline

....yep, the early 4 strokes never came with locknuts. The Saito engine is the most
prone to backfire and throw props because they run higher compressions than the
others.

FBD.

_____________________________

An engineer says.... "That won''t work".
A mechanic says..."Oh yeah, watch this".
"Old Age, and Treachery will overcome youth and skill".
Revver Bro #4.

(in reply to Motorboy)

RE: 4-stroke without a locknut? - 7/9/2007 11:18:31 PM

Posts: 560
Joined: 4/8/2007
From: ISTANBUL, TURKEY
Status: offline

an addition: an over primed starting attempt and running overly rich can also cause a sudden backfire due to the plug filament getting too wet and losing its heat.

_____________________________

LiQuid TR

(in reply to Flyboy Dave)

RE: 4-stroke without a locknut? - 7/9/2007 11:28:06 PM

Posts: 1098
Joined: 10/12/2005
From: TEDA (Tianjin)Tianjin, CHINA
Status: offline

I have 3 or 4 running without the locknuts, never had a problem.
As the others have said - it's only a problem if you have a backfire.

_____________________________

Australian agent for
RCGF engines & Boxes, 33RC airframes, Tzone models, Super Kraft (SK) & others

(in reply to liquid_TR)

RE: 4-stroke without a locknut? - 7/10/2007 1:01:11 AM

Posts: 1368
Joined: 12/11/2002
From: USA, USA
Status: offline

RVM

Check the adapter kits from TruTurn. They have a short shaft set up that works extremely well and uses the lock concept.

The spinner mounts easily too. Check for the 8 x 1.25 size for your 100 and right on up the scale too.

Edit addition: TT-0822-A is the adapter kit number.

< Message edited by onewasp -- 7/10/2007 1:06:07 AM >

_____________________________

The ground reached up and smote my airplane

(in reply to RVM)

RE: 4-stroke without a locknut? - 7/10/2007 1:28:18 AM

Posts: 147
Joined: 9/8/2003
From: Bogota, COLOMBIA
Status: offline

I've been running an OS 52 four-stroke with a spinner nut (no locknut, of course) for quite a while, and ... never a problem.

Enjoy.

Misterpanda

(in reply to RVM)

RE: 4-stroke without a locknut? - 7/10/2007 3:15:52 AM

Posts: 8004
Joined: 1/31/2002
From: Ringgold, GA, USA
Status: offline

quote:

ORIGINAL: Flyboy Dave

....yep, the early 4 strokes never came with locknuts. The Saito engine is the most
prone to backfire and throw props because they run higher compressions than the
others.

FBD.

------------

One of the reasons that Saito became a favored engine with many was because of their solid thump when idling. This was directly the effect of running higher compression than many other engines.

Ed Cregger

_____________________________

"Flying models since the Fifties"

Saito Club Member #52

(in reply to Flyboy Dave)

RE: 4-stroke without a locknut? - 7/10/2007 3:37:32 AM

Posts: 1102
Joined: 1/7/2004
From: fort worth, TX, USA
Status: offline

Locknut or not, you should never stand next to or in front of a fourstroke at any power level above idle. All of them are prone to throwing props.

(in reply to Ed Cregger)

RE: 4-stroke without a locknut? - 7/10/2007 3:50:01 AM

blw

Posts: 4608
Joined: 3/15/2004
From: Auburn, AL, USA
Status: offline

I think your impressions of Saito engines comes from a long time ago, and probably with the older model Saito .80s.

Saitos are the mildest running engines around. It is hard to get one to actually backfire, and when they do the ones I've seen only loosen the nuts some. Very forgiving low compression engines.

I would vote any YS 4 stroke as the one to have the nastiest backfires.

_____________________________

The ultimate responsibility of pilots is to fulfill the dreams of the countless millions who can only stare skyward...and wish.

(in reply to Kweasel)

RE: 4-stroke without a locknut? - 7/10/2007 5:51:50 AM

XJet

Posts: 3596
Joined: 3/31/2003
From: Tokoroa, NEW ZEALAND
Status: offline

I've even run my TT91FS without a locknut (so I could fit a spinner) and had no problems -- apart from the occasional backfire when starting that merely loosened the prop (didn't throw it).

As for Saitos -- they are perhaps the *sweetest* 4-strokes on the market when it comes to immunity to backfiring.

I don't think any of mine have ever even hinted at backfiring or throwing a prop.

Remember that proper tuning is critical to exactly how balky a 4-stroke is. Don't over-lean them and you'll have no problems.

_____________________________

When I'm not here, I'm at RCModelReviews

(in reply to blw)

RE: 4-stroke without a locknut? - 7/10/2007 7:08:45 AM

Posts: 13513
Joined: 3/20/2002
From: San Bernardino County, CA, USA
Status: offline

quote:

ORIGINAL: blw

I think your impressions of Saito engines comes from a long time ago, and probably with
the older model Saito .80s.

Saitos are the mildest running engines around. It is hard to get one to actually backfire,
and when they do the ones I've seen only loosen the nuts some. Very forgiving low compression engines.

Saito engines have always had the highest compression ratios on Planet Earth.
Do you have any proof that they are "the mildest running engines around".
Please post this information.

The fact is....Saito has strived from it's onset to be the most powerful normally aspirated engine
manufacturer around. Their advantage comes from their high compression, and from their straight
cut cam gears. This is not a secret.

They also have the Worlds record for "prop throwing"....

....here are a few examples....right here on RCU.

http://www.rcuniverse.com/forum/m_485558/mpage_1/key_threw%2Cprop/tm.htm

Post #6, 12, 13, 17, 19, 24, 30.

http://www.rcuniverse.com/forum/m_5739033/anchors_5739033/mpage_1/key_threw%252Cprop/anchor/tm.htm#5739033

http://www.rcuniverse.com/forum/m_4701392/anchors_4701392/mpage_1/key_threw%252Cprop/anchor/tm.htm#4701392

http://www.rcuniverse.com/forum/m_4087709/anchors_4087709/mpage_1/key_threw%252Cprop/anchor/tm.htm#4087709

http://www.rcuniverse.com/forum/m_3042670/anchors_3042670/mpage_1/key_threw%252Cprop/anchor/tm.htm#3042670

http://www.rcuniverse.com/forum/m_1723235/anchors_1723235/mpage_1/key_threw%252Cprop/anchor/tm.htm#1723235

http://www.rcuniverse.com/forum/m_906956/anchors_906956/mpage_1/key_threw%252Cprop/anchor/tm.htm#906956

http://www.rcuniverse.com/forum/m_873634/anchors_873634/mpage_1/key_threw%252Cprop/anchor/tm.htm#873634

http://www.rcuniverse.com/forum/m_782025/anchors_782025/mpage_1/key_threw%252Cprop/anchor/tm.htm#782025

http://www.rcuniverse.com/forum/m_644886/anchors_644886/mpage_1/key_threw%252Cprop/anchor/tm.htm#644886

http://www.rcuniverse.com/forum/m_379911/anchors_379911/mpage_1/key_threw%252Cprop/anchor/tm.htm#379911

http://www.rcuniverse.com/forum/m_182154/anchors_182154/mpage_1/key_threw%252Cprop/anchor/tm.htm#182154

....thanks,

FBD.

< Message edited by Flyboy Dave -- 7/11/2007 5:26:11 PM >

_____________________________

An engineer says.... "That won''t work".
A mechanic says..."Oh yeah, watch this".
"Old Age, and Treachery will overcome youth and skill".
Revver Bro #4.

(in reply to blw)

RE: 4-stroke without a locknut? - 7/10/2007 2:52:40 PM

Posts: 1368
Joined: 12/11/2002
From: USA, USA
Status: offline

They also have the Worlds record for "prop throwing".

You MUST be referring to the earlier high compression designs-----the current variety are quite mild to handle and will only loosen the nuts when started too lean only. No, I would not choose to prop one and yes you can do the 'spinner back flip' start though I choose not to.
While the ratio may seem high in numerical expression it currently is lower than earlier models.

Currently I am flying the 82a and 180. I have owned a number of others.

I've yet to see a prop thrown from a Saito (with a locking nut set-up) and I've been around a long time and have flown at many fields over that period.

PS I did not wade through your citations but if there is one you find particularly germane let me know please.

< Message edited by onewasp -- 7/10/2007 2:53:19 PM >

_____________________________

The ground reached up and smote my airplane

(in reply to XJet)

RE: 4-stroke without a locknut? - 7/10/2007 4:02:04 PM

RVM

Posts: 1975
Joined: 3/12/2006
From: Sacramento, CA, USA
Status: offline

Thanks for all the replies! I'll see how it goes without one for a bit.

_____________________________

There is no substitution for human competition.

(in reply to onewasp)

RE: 4-stroke without a locknut? - 7/10/2007 4:57:02 PM

Posts: 13513
Joined: 3/20/2002
From: San Bernardino County, CA, USA
Status: offline

....here ya' go, onewasp....I'll make it easier for you....

If you do a search here at RCU for
"throw prop" (just in glow engines Forum) you will see that Saito has thrown about 10 times
as many props as the others combined.

post #5
http://www.rcuniverse.com/forum/m_4811234/anchors_4811234/mpage_1/key_throw%252Cthrew%252Cprop/anchor/tm.htm#4811234

http://www.rcuniverse.com/forum/m_5739033/anchors_5739033/mpage_1/key_throw%252Cthrew%252Cprop/anchor/tm.htm#5739033

http://www.rcuniverse.com/forum/m_4087709/anchors_4087709/mpage_1/key_throw%252Cthrew%252Cprop/anchor/tm.htm#4087709

....in Canada....

http://www.rccanada.ca/bb/viewtopic.php?t=34647

This is not new news, it is not a secret.....Saitos throw a lot of props, always have.

FBD.

_____________________________

An engineer says.... "That won''t work".
A mechanic says..."Oh yeah, watch this".
"Old Age, and Treachery will overcome youth and skill".
Revver Bro #4.

(in reply to RVM)