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Cox Engine of The Month
Pee Wee 020 running backwards
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Pee Wee 020 running backwards
Hi all-
I have a Pee Wee 020 that starts up and runs strong EXCEPT it is running backwards! Did I reassemble it the wrong way or something?
Any input is appreciated.
Thanks,
Bob
I have a Pee Wee 020 that starts up and runs strong EXCEPT it is running backwards! Did I reassemble it the wrong way or something?
Any input is appreciated.
Thanks,
Bob
rfara- Moderate Poster
- Posts : 24
Join date : 2022-03-09
Re: Pee Wee 020 running backwards
The great thing about reed valve engines is that they will run either way. Put on a left hand prop, run clockwise as seen from the front. Put on a right hand prop, run counterclockwise. It just happens that most propellers are cast/cut for counterclockwise rotation as seen when starting. Why do we call a prop that runs counterclockwise a right handed prop? Well, we start our model engines looking at them from the front, but prop terminology as developed in the aviation industry looks at prop rotation from the rear, where the pilot would be sitting.
Are you using the spring starter to start the engine or are you hand flipping the prop?
The Widdershins Mark
Are you using the spring starter to start the engine or are you hand flipping the prop?
The Widdershins Mark
batjac- Diamond Member
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Posts : 2375
Join date : 2013-05-22
Age : 61
Location : Broken Arrow, OK, USA
Re: Pee Wee 020 running backwards
Thanks. Hand flipping it. Should I flip the prop clockwise, from the front view, to get it to run counter clockwise, from the front?
Or just install the spring starter?
Or just install the spring starter?
rfara- Moderate Poster
- Posts : 24
Join date : 2022-03-09
Re: Pee Wee 020 running backwards
rfara,
If your Pee Wee is like mine:
If you use the spring starter, you engage the prop's trailing edge of the prop into the part of the spring that is behind the prop.
Now, with the spring on the backside of the prop. turn the prop/spring clockwise (looking from the front as in the above photo) about 1/2 a turn (or so). You don't need to crank the prop over to where the spring is tightly wound. (about 3 turns)
doing so can damage the spring (bent out of shape.)
I usually hold the prop by the tip for this --- Now let the prop tip go!
With the spring starter, it will turn the prop counterclockwise and will blow the prop air (prop wash) over the engine.
That is "if" you have the correct tractor prop on it and not a pusher (reverse) prop on the engine.
Mike
If your Pee Wee is like mine:
If you use the spring starter, you engage the prop's trailing edge of the prop into the part of the spring that is behind the prop.
Now, with the spring on the backside of the prop. turn the prop/spring clockwise (looking from the front as in the above photo) about 1/2 a turn (or so). You don't need to crank the prop over to where the spring is tightly wound. (about 3 turns)
doing so can damage the spring (bent out of shape.)
I usually hold the prop by the tip for this --- Now let the prop tip go!
With the spring starter, it will turn the prop counterclockwise and will blow the prop air (prop wash) over the engine.
That is "if" you have the correct tractor prop on it and not a pusher (reverse) prop on the engine.
Mike
Last edited by sosam117 on Wed Mar 22, 2023 3:48 pm; edited 1 time in total
sosam117- Diamond Member
- Posts : 1351
Join date : 2016-03-23
Location : Suburb of Chicago, Illinois
Levent Suberk- Diamond Member
- Posts : 2265
Join date : 2017-12-24
Location : Türkiye
Re: Pee Wee 020 running backwards
Mine is exactly like yours except a bit more aged visually, if you know what I mean. Also, I am using a seperate eyedropper type tank and running the fuel iine into the existing tank mount through a small hole that I drilled.
I currently do not have a spring starter on it because it was starting easily. As far as I know, I have tractor props only. I will install a spring starter and go from there. Thanks for the explanation.
I currently do not have a spring starter on it because it was starting easily. As far as I know, I have tractor props only. I will install a spring starter and go from there. Thanks for the explanation.
rfara- Moderate Poster
- Posts : 24
Join date : 2022-03-09
Re: Pee Wee 020 running backwards
A few things can be causing the reverse rotation. I use them on eyedropper tanks myself. If the eye dropper is too high the head pressure in the dropper begins to flood the engine until the level drops. If the ball socket has excessive play it can cause the engine to run forward, then reverse and even back again. The most common cause though is over priming. The reed valve could also not be sealing properly. The spring starter can help but I've had it still run backwards. I toss a rag in it and quickly fire it up until it's running forward.
Ken Cook- Top Poster
- Posts : 5642
Join date : 2012-03-27
Location : pennsylvania
Re: Pee Wee 020 running backwards
When there is no spring starter, sometimes flipping it the other direction will cause it to fire in the right direction. I've had times when I had to do similar to Ken, toss a rag into the prop to stop it may be 3 or 4 times, until it is going right.
In another case with a slightly larger engine, an Enya. 09-III TV with muffler, it refused to run reliably with heavier plastic props, could not get it to reliably needle right. But then, tried a Top Flite wood 7x6, started right up and needled easily. For some reason, the engine did not like the heavier inertia plastic props.
At times, you have a day in which everything goes right. Other times, engines have a mind of their own. I wish there was a secret for it to start the way it is supposed to, but short of a mini-electric starter, which I wouldn't use anyway because it sometimes imparts extra wear and tear I'd like to not deal with, but so far I have found none.
In another case with a slightly larger engine, an Enya. 09-III TV with muffler, it refused to run reliably with heavier plastic props, could not get it to reliably needle right. But then, tried a Top Flite wood 7x6, started right up and needled easily. For some reason, the engine did not like the heavier inertia plastic props.
At times, you have a day in which everything goes right. Other times, engines have a mind of their own. I wish there was a secret for it to start the way it is supposed to, but short of a mini-electric starter, which I wouldn't use anyway because it sometimes imparts extra wear and tear I'd like to not deal with, but so far I have found none.
GallopingGhostler- Top Poster
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Posts : 5724
Join date : 2013-07-13
Age : 70
Location : Clovis NM or NFL KC Chiefs
Getting Pee Wee running in the correct direction
I spent quite a bit of time with this delightful engine. Control line free flight and even that airboat that made the engine of the month picture a while back. When this little engine starts in reverse I would just put the palm of my (bare) hand into the prop disc and it would stop; no fuss no muss. The blades are not "biting" when running in reverse and the engine has only minimal power.
I never liked the spring starter. Besides, it adds extra weight!
I never liked the spring starter. Besides, it adds extra weight!
Last edited by 706jim on Wed May 03, 2023 2:39 pm; edited 1 time in total
706jim- Gold Member
- Posts : 472
Join date : 2013-11-29
Re: Pee Wee 020 running backwards
Thank you all for the feedback and information. Initially, I will install a spring starter and if that doesn't solve the problem, I will check some of the other possible causes. I will include a picture of the engine installed and location of the external eyedropper tank with respect to the engine. I don't think that it is much higher.
rfara- Moderate Poster
- Posts : 24
Join date : 2022-03-09
Re: Pee Wee 020 running backwards
Luckily the spring starter solved the problem. The engine ran strong in the correct direction. Can't wait to get out there and test the plane!
Thanks to all.
Thanks to all.
rfara- Moderate Poster
- Posts : 24
Join date : 2022-03-09
Re: Pee Wee 020 running backwards
rfara wrote:Luckily the spring starter solved the problem. The engine ran strong in the correct direction. Can't wait to get out there and test the plane!
Thanks to all.
Glad the spring starter helped out.
As for the weight of the spring (16 grams), there are other places on the plane you can do to reduce the weight?
The slight weight of the starter spring is negligible.
I use the spring starter because, for me, it makes starting these small engines easier.
sosam117- Diamond Member
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Join date : 2016-03-23
Location : Suburb of Chicago, Illinois
Re: Pee Wee 020 running backwards
sosam117 wrote:
Glad the spring starter helped out.
As for the weight of the spring (16 grams), there are other places on the plane you can do to reduce the weight?
The slight weight of the starter spring is negligible.
The Pee Wee is supposed to be 21 grams. if so I doubt that the starter spring would weigh 16 grams.
706jim- Gold Member
- Posts : 472
Join date : 2013-11-29
Re: Pee Wee 020 running backwards
706jim wrote:sosam117 wrote:
Glad the spring starter helped out.
As for the weight of the spring (16 grams), there are other places on the plane you can do to reduce the weight?
The slight weight of the starter spring is negligible.
The Pee Wee is supposed to be 21 grams. if so I doubt that the starter spring would weigh 16 grams.
Maybe 0.6 grams? Fat fingered the "one"?
Just took a guess at the weight?
sosam117- Diamond Member
- Posts : 1351
Join date : 2016-03-23
Location : Suburb of Chicago, Illinois
Re: Pee Wee 020 running backwards
Sceptre Flight Model Engine Tests: Cox Pee Wee 020 (2)Peter Chinn in March 1976 Aeromodeller wrote:Checked Weights: 24.5 grammes - 0.86 oz.
(with starter spring)
23.0 grammes - 0.81 oz.
(less starter spring)
Thus, the spring starter adds 1.5 grammes - 0.05 oz.
GallopingGhostler- Top Poster
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Posts : 5724
Join date : 2013-07-13
Age : 70
Location : Clovis NM or NFL KC Chiefs
Re: Pee Wee 020 running backwards
GallopingGhostler wrote:Sceptre Flight Model Engine Tests: Cox Pee Wee 020 (2)Peter Chinn in March 1976 Aeromodeller wrote:Checked Weights: 24.5 grammes - 0.86 oz.
(with starter spring)
23.0 grammes - 0.81 oz.
(less starter spring)
Thus, the spring starter adds 1.5 grammes - 0.05 oz.
and some people worry about the extra weight of the spring?
sosam117- Diamond Member
- Posts : 1351
Join date : 2016-03-23
Location : Suburb of Chicago, Illinois
Re: Pee Wee 020 running backwards
I suppose if someone was an all out competition flier and was scrutinizing removing weight to the extremes including not needed washers, use of thinner planking, alternate structural materials, may be yes, 0.05 oz. shaved off my be considered significant. If one needs to ballast though for CG, then a mute point.
In R/C use I'd say the weight was negligible, even in sport F/F. I found the starters to be very useful in having flight after flight. Once my rudder only ship came in and deadstick landed, I'd fuel up and was off flying in short order, may be putting in close to a dozen flights before calling it quits. (With a 1.5 to 2.5 minute run time depending on prop, one needed/wanted flight after flight to have a fun day.)
In R/C use I'd say the weight was negligible, even in sport F/F. I found the starters to be very useful in having flight after flight. Once my rudder only ship came in and deadstick landed, I'd fuel up and was off flying in short order, may be putting in close to a dozen flights before calling it quits. (With a 1.5 to 2.5 minute run time depending on prop, one needed/wanted flight after flight to have a fun day.)
GallopingGhostler- Top Poster
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Posts : 5724
Join date : 2013-07-13
Age : 70
Location : Clovis NM or NFL KC Chiefs
Re: Pee Wee 020 running backwards
sosam117 wrote:............
and some people worry about the extra weight of the spring?
GallopingGhostler wrote:............
In R/C use I'd say the weight was negligible, even in sport F/F. I found the starters to be very useful in having flight after flight.
I have just weighed an .049 starter spring, designed for use with the ratchet disk (without the disk). Weight on my DEA drug scale was 2.63 grams. I think it's a valid assumption that the .020 spring will be even lighter. In viewing plans over the years, it is pretty obvious that construction is lighter now and radio gear is in a whole different magnitude WRT to weight.
If it comes down to flippin' or flyin', worrying about spring weight is much ado about nothing.
a--
Re: Pee Wee 020 running backwards
Hi Bob, Well.. there's plenty of advice for ya'... I've used the spring-starters and they work very well at making sure that the engine starts in the direction intended. In my opinion; their negligible weight is a non-factor.
When you're trying to start one of these precious little mills.. you don't want to waste any time.. especially if you're in a situation where you've got limited battery capacity for starting.
As mentioned previously in the thread; you only need to wind-back the spring enough to cycle the engine through one stroke to start it.. providing it has decent compression (IE: will start and run via hand-propping) Excessive winding of the spring will not only shorten the spring's life.. but can/will scuff-up the anodizing on the nose of the crankcase.
When you're trying to start one of these precious little mills.. you don't want to waste any time.. especially if you're in a situation where you've got limited battery capacity for starting.
As mentioned previously in the thread; you only need to wind-back the spring enough to cycle the engine through one stroke to start it.. providing it has decent compression (IE: will start and run via hand-propping) Excessive winding of the spring will not only shorten the spring's life.. but can/will scuff-up the anodizing on the nose of the crankcase.
Re: Pee Wee 020 running backwards
Great responses. Thank you all. I have a number of Pee Wee 020 engines that I am slowly cleaning up and refurbishing. Some of them have issues so I use them for parts.
Bob
Bob
rfara- Moderate Poster
- Posts : 24
Join date : 2022-03-09
Re: Pee Wee 020 running backwards
GallopingGhostler wrote:I suppose if someone was an all out competition flier and was scrutinizing removing weight to the extremes including not needed washers, use of thinner planking, alternate structural materials, may be yes, 0.05 oz. shaved off my be considered significant. If one needs to ballast though for CG, then a mute point.
As always, it's a tradeoff. Back in the the 90's I flew Speed 400 (electric 1/2A) with only two screws in the 9gram GWS servo cases. I once had half a flight with no aileron horn screw. Can't say that was intentional.... or productive after excavating the nose from the mud.
gkamysz- Gold Member
- Posts : 417
Join date : 2018-02-22
Location : Chicagoland
Guys I was just joking about the Pee Wee starter spring weight!
..like it says in the subject line....
706jim- Gold Member
- Posts : 472
Join date : 2013-11-29
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