build Peggy Sue 2

[Peter Miller]

All the Peggy Sues fly straight and level well.

You might get a swing on take off but you can get that even if you have side thrust. That is what the rudder is for.

If it doesn't fly straight and level in normal flight you then use the trim switches to trim out any miss alignment due to construction errors

 

 

[Peter Miller]

Thinking about the above.

So you add side thrust and down thrust to make the model fly straight and level.

Now suppose that you find that it doesn't fly straight and level when you take it to the field. What do you do?

 

Take the engine out and add more side or down thrust!?  If you have used side or down thrust to get the model to fly straight the logical thing to do would be to alter the side and down thrust to correct any deviation from straight and level.

 

Or do you apply some trim. And you apply trim to correct the deviation to correct any deviation due to incorrect side and down thrust why not apply it in the first place?

[john stones 1 - Moderator]

I would trim with packing pieces on the day until I'd reached the correct amount of side/down, only thing that can tell you the correct amount is flying it, as we all may use different engines props it's the only way, bit of faffing but the most elegant solution.

[Peter Miller]

These flew perfectly with no side or down thrust and very little trim adjustment.

[Graham Davies 3]

I am the lucky owner of Peter's Peggy Sue. I can testify that it is rigged zero/ zero (I converted it to electric!). Whilst I could argue a case for downthrust, I can't really say that the model needs either. With a bit of attention to the rudder trim, it loops straight, and flies circuits fast or slow without significant retrimming. As Peter has seen, it flies uplines for stall turns pretty straight, and I can tool around in slow low circuits without any real issue. However, it is extremely aerobatic if you open the taps,

 

If I were you EB, rig it zero zero. If you can fly solo, you won't have any trouble and you'll love it.

 

Graham

 

 

[EarlyBird]

Thanks Graham, it looks like this is going to be a committee decision (compromise🤣). My thinking is that the motor causes torque and right thrust or rudder trim counteracts it. Similarly a high wing causes the nose to lift and down thrust or elevator trim counteracts it. It strikes me that Peter's designs need so little trim it makes thrust changes irrelevant. 

 

Still thinking.

 

Steve

 

 

[Graham Davies 3]

Yes Steve. There will always be a torque reaction, but I have managed to easily trim my PS so it flies pretty straight, regardless of throttle position. It doesn't 'zoom' under power and any torque reaction is easily managed. I fly mine on a big old 14x8, and even so it's quite benign and neutral.

 

Like Peter, I can't remember when I last applied any changes to the thrustline of a model. I can't imagine you'll have any issues if you rigg it at zero/ zero.

 

Graham

[Peter Miller]

One point to notice.  My wings are set at zero degrees incidence so in fact it does not give lift unless it is fractionally nose high.

 

I keep telling people to read Kermode's "Flight Without Formulae"

[kc]

Has anyone mentioned that side thrust means adjusting the engine mount so the cowl fits nicely?   It's easier without side thrust or downthrust!

[EarlyBird]

7 minutes ago, kc said:

Has anyone mentioned that side thrust means adjusting the engine mount so the cowl fits nicely?   It's easier without side thrust or down thrust!

I have already included for 2 Deg. side thrust fortunately no glue has been applied so I can easily move the claw nuts. I do find the best way to learn is by making mistakes 🤣

[Peter Miller]

KC is another follower of my great belief in the KISS principle!

[Outrunner]

My understanding is the propwash spiraling down the fuselage causes the swing on take off no a torque reaction

[kc]

One of the main points of the Keep It Simple principle  is " If it ain't broke don't fix it "

 

 

 

Peter, all followers of your designs and principles are eagerly awaiting your next plan..............

[Peter Miller]

I recently watched US carrier fighters taking off from Carriers.  They used vast amounts of right rudder as they started their take off runs.

[Peter Miller]

42 minutes ago, kc said:

One of the main points of the Keep It Simple principle  is " If it ain't broke don't fix it "

 

 

 

Peter, all followers of your designs and principles are eagerly awaiting your next plan..............

Well The next is NOT exciting, It is an electric conversion of the Dick Schumaker Little Ship.

These days I just can't raise the energy, strength or interest to start drawing  and creating a new design. So don't hold your breath 'cos I don't have a a lot of breath left

[Martin Harris - Moderator]

3 hours ago, Outrunner said:

My understanding is the propwash spiraling down the fuselage causes the swing on take off no a torque reaction

Probably the major contributor in models but torque reaction loads the left wheel, adding to the swing. On a taildragger, there’s also an asymmetric thrust effect  (p factor) pulling to the left when the tail is down and when it lifts its tail the propeller is subjected to gyroscopic precession - which adds (you guessed it) a left yaw…

 

Luckily, all these effects can be countered by skilful application of right rudder.   Some right thrust gives a measure of “automatic” compensation but it will always be an approximation and learning to use the rudder is an essential skill. 

 

 

[john stones 1 - Moderator]

Taking off is a basic skill and not the reason I or others I would presume, go to the effort of faffing with side thrust, much more involved in the reason I personally do it. And I 'll leave it at that, E.Bs threads about his build so look forward to it progressing.

[EarlyBird]

This build is on hold while I complete Hound Dog which is now at the covering stage. I have included side thrust, as a test, which will be adjusted as required. The aim being to fly with no rudder trim required, just for fun. I do find it interesting that models can be set at 0/0 and the trims used to correct for side and vertical forces and yet others for example last years Mini Super has 2.5 Deg. side thrust built in. A subject for another topic I am thinking.

 

Still thinking about this build though. I will probably build 1 Deg. side thrust in and test fly then adjust and finally build the cowl. Having said that I could change my mind.🤣

 

Steve 

[Ron Gray]

I checked my PS2 and no side or downthrust and having checked my Tx no rudder or elevator trims just a bit of aileron.

[Piers Bowlan]

2 minutes ago, Ron Gray said:

I checked my PS2 and no side or downthrust and having checked my Tx no rudder or elevator trims just a bit of aileron.

Ron, if your PS2 wings weigh the same (model laterally balanced) and it has a slight tendency to roll with no aileron trim applied, it may well be rolling as a further effect of yaw caused by the propeller slipstream. A small amount of rudder trim may also correct a tendency to roll as one is a further effect of the other. This is just theoretical and of no consequence to how one flies. Engine offset (or not) is a matter of personal preference.

All the above assumes no warps of course (I will quickly add, most unlikely with Ron’s model!)

[Ron Gray]

@Piers Bowlanyou are quite correct in that rudder trim may have the same effect as aileron trim and on the PS2 the rudder is very effective! TBH I can't remember if I also tried rudder trim but the maiden was carried out in somewhat of a stiff breeze (gale!), I think I posted the vid of that flight on here!

[Peter Miller]

25 minutes ago, Ron Gray said:

@Piers Bowlanyou are quite correct in that rudder trim may have the same effect as aileron trim and on the PS2 the rudder is very effective! TBH I can't remember if I also tried rudder trim but the maiden was carried out in somewhat of a stiff breeze (gale!), I think I posted the vid of that flight on here!

I saw that Video.I still quote the verdict after the flight...and it was a howling gale. The smoke in the back ground was blowing horizontally  straight from the chimney

[Ron Gray]

A plane for all seasons! 🤣

[Piers Bowlan]

1 hour ago, Ron Gray said:

A plane for all seasons! 🤣

I will have to put it on my build list (it’s a long list!)

[EarlyBird]

I went flying this morning and used the last 5.25l of fuel in the FG21, only taken me four years. Hmm I thought I need to run the FG11 in which made me think of this build.

 

F1 now glued in 

 

and UC side plates adjusted to make them offset.

 

Steve