Cees,

As I suspected we are completely off topic. I thought this had to do with my learning curve and D-tube holes. Now you've decided to discuss Ralph's power supply which has, again, no bearing. If you preach exactitude, engineering and calculations, stay focused - stay on topic, don't take me for a walk in the wild.

In any case, you completely misunderstood me in the post you've chosen to quote me on above (as expected - a runaround of past information with no relevance). I was not burning those PSU's down, I was elevating Ralph's!

I don't doubt they are excellent PSU's and for that reason I mentioned they looked suited for a hospital but that was Ralph's foam cutting PSU build thread. Interjecting the fact that perfectly usable supplies exist for a foam cutter in someone's purpose built hobby supply is somewhat rude. I'm sure Ralph was well aware he could buy one if he chose to but what he chose to do was to build one for himself. And of all people you are often suggesting to others to build everything by hand which is a nice approach I admit. Sometimes others might prefer to use a commercial hooded pushrod exit guide even if it doesn't conform to your sense of aerodynamics. In this case Ralph chose to build something and you highlighted that there was no need for him to do so since he could just buy one... and not risk blowing up his house... c'mon Cees. The safety of other adult modelers is not really your concern. This is a fun hobby space not an academic safety classroom.

You present things as if you already know all possible future outcomes of people's foolish acts. That's simply unrealistic and unpleasant.

Whatever the case, Ralph has his reasons, and whether they do or do not suit your PSU choice parameters is irrelevant. His build has nothing to do with what you might select or buy - it's his supply, not yours.

Finally, I'd rather promote the sale of Ralph's tested and working PSU as I'd rather stimulate grass roots efforts rather than large commercial efforts. I wouldn't doubt they have a capable marketing and sales department and have no need for either your or my promotion efforts.

Why I'm discussing any of this is beyond me. I'm not sure you have ever been willing to meet others half ways - find a common ground of communication.

Above, you chose to dismiss someone's comment and opinion on the SP I built. You then proceeded to inform them of their complete ignorance on all matters based on some RCU parameters you plucked from user accounts. Doesn't that strike you not only as poor judgment on your part but rather disrespectful? After all, what do you know about that person? Close to nothing, I'd say. In English that is called arrogance and is generally not considered a desirable quality. Be respectful, offer your point of view but let others have theirs and above all, don't assume that if someone does something differently from how you do it, they are a lesser person than you are - from a craft standpoint, academically, professionally, intellectually or otherwise. We know very little about people from online exchanges - it is only fair to give everyone the benefit of the doubt and extend common courtesy.

I'm sure we both have better things to do than continue with this line of exchange.

David.

I completed a Super Pacer that I started years ago, powered mine with an OS 25 (would be better with the ST 23) Flies great and was easy to build. I was thinking about making it 40 sized.........

Epr3,

do show us some pics of your SP! Was the OS 25 too heavy or did it seem overpowered? Which OS is it? How much does she weigh?

David.

Hi David,

I have a couple of questions for you.

1) F2 (the former right before the wing) is a bit taller than the fuse. The result is that the bottom piece with the pre-drilled hole (for the 3/16" dowel that holds the front of the wing) extends too far. Iplan on sanding F2 to fit and re-drilling the hole. Did you experience anything similar?

2) From the plans "Install the control linkages and add the 1/8" crossgrained bottom (Furnished as 1/8" x 3" x 12")". There is no further indication of routing the linkages, length, etc and only a vague reference in the plans to the servo locations. In fact, the planes only refer to 3 servos. Can you provide input (and maybe pictures) of how you installed and routed your linkages and placement of servos? A am assuming that one linkage will exit the fuse side on the right and one on the left for the rudder and elevator. The ailerons look straight forward. How did you route (and place servo) for throttle?

3) Were there any other instructions other than the plans that came with this kit?

The only other kits I built were SIGwith nice, step-by-step directions, so inferring what to do with this kit is fun!For example, Istill don't know what the word 'strake' means, but I think I know where to put them.

Thanks!

Hi there, is it Ian? (just guessing)

1) I mentioned a few posts back that the wood cutting and sizing was not great. The fuse sides lay down the planform (an overall side or top view) of the model so if those are properly sized and, most of all, equal then the fuse build usually proceeds more smoothly. Because my fuse sides left much to be desired, I went ahead and used the long one as a rough master. I wanted a symmetric fuse with full length sides and also was going electric so I cut back from 1/8" wood stock to 3/32" which is a more common fuse side stock for 25 size models. In cutting the sides, I checked the formers first to see if they were cut properly and found them to be acceptable. I do recall having to sand them both a bit so they would fit snug within the triangle stock provided (or I might have used my own). Go ahead and sand the bottom (or the top, whichever seems to make most sense based on the fit) down to height and adjust the angle cuts for the tristock accordingly. The cuts are at 45 degrees.

As far as the leading edge dowel goes, a single 3/16" dowel struck me as an accident waiting to happen. Whenever possible, I rather go with two dowels or a rather beefy center section keel that extends from the wing center and is captured by an equivalent opening in the wing LE former. In my case, I was installing retracts which meant that a retract servo (they are mechanical retracts) would go in the front LE section of the wing. This precluded the use of a single dowel as well and I installed two 3/16" on either side of the retract servo. The installation of the servo and dowels as well as the supporting wood in that area was a little tricky since the servo is large and barely fits chordwise in the wings LE. But this probably won't apply to your build other than a recommendation to go with two dowels (especially if they are 3/16" and you are using glow power). It helps to get the dowels lined up, installed and backed up with a piece of 1/16" ply bonded to the front of the spars before sheeting the bottom of the wing. The ply on the spars makes for a stronger wing support. I had to resort to other methods because I have retract pushrods where the dowels would normally be passing through.

2) The radio and pushrod installation in a model like this is very conventional. There is a wide open bay above the wing for this. Typically, one positions and installs all the power train gear first (engine, muffler, prop, spinner, tank, etc.) and then, with the model fully assembled (omit the lower fuse sheeting for the moment), you position your battery and servos so that the model balances where required. You can put the battery and servos on top of the fuse, balance the model and shift the gear on top of the fuse until the model balances. Typically, you'll end up with the battery in the front part of the radio bay, the receiver after that and the servos toward the back near the wing TE former. This is a convenient arrangement. In some cases though, you need to locate the battery in the fuel tank area so that the model balances. On the SP this is not desirable as the fuel tank area will be occupied by en large by the tank. Having to put the battery there will limit your fuel tank size and type. It is preferable to lighten your tail feathers where possible and keep the battery behind the former in the radio bay as described. This also protects it from any eventual fuel spills in the tank area (which should be fuel proofed - thinned epoxy works well for this).

I've attached a shot of where my servos are placed for balance but my model is different from yours in that I built it "off-stock" with light tail feathers and different weight of wood for the sides, top and bottom. I am also using electric power and because of this, my model only has a 3s or 4s Li-Po battery pack, no fuel tank and no throttle servo. For your model, I good arrangement for the fuse servos would be to install the elevator and rudder servos side by each (much like I did) and the throttle servo just in front of those mounted sideways with the output arm on the correct side for routing a flexible pushrod to the throttle barrel on the carburetor. A 1/16" ply servo tray might help to get the servos installed as needed and you might as well provide some space for the receiver to be mounted. The battery can be wrapped in foam and placed ahead of the tray. I attached a photo of another model with this type of radio install.

For pushrods, I used very conventional "nyrod" type plastic pushrods in plastic sleeves with threaded piano wire ends to attach to the servos. I braced the pushrods along the length of the rear of the fuse with small rectangular pieces of 3/16" balsa but you can use whatever you have provided it is sturdy enough (you can use 1/16" ply as well or even 1/8" hard balsa). It is important to not let the pushrods flex as otherwise the servo movement doesn't transfer to the control properly - you probably are familiar with this. Likewise with the throttle flexible pushrod (Great planes or Du-Bro) - brace it in 2 or 3 places on its way to the throttle arm. I believe the kit includes some pushrods which are full length piano wire. Again, since I was going for a light electric model, I replaced these with nylon versions.

The linkages do indeed exit each fuse side to control the elevator and rudder. The elevators are joined per plans so you only need a single control horn on each control surface. I routed my elevator linkage out the left side of the model and the rudder on the right but it doesn't really matter. It is an issue of cosmetics. Often we attempt to leave on side of the model "clean" and on classics this is usually the left side of the model since the right side has the engine and muffler (or only muffler in upright installations) exiting the side. Linkage routing has some bearing on this.

For the ailerons you can either use torque rods (provided I think) or use two servos as I did - one for each aileron (I am not a fan of torque rods). I don't believe there were any other instructions but to be honest, I might have missed them since the build is fairly conventional. By the way, I also used two nylon wing retaining bolts in the rear into a 1/4" ply plate. The four retention points gives some peace of mind when doing high G maneuvers (loops, snaps, etc.)

My firewall didn't fit at all but again I needed a much lighter one for electric power so I cut another that did fit. Most of my kit was left in the box except for the canopy, the two lite-ply formers and the wing ribs. I also left the spars in the kit as I believe they were quite warped and I think also spruce (I used balsa). One thing that you might want to do is to "bind" the ribs and spars together with what are called shear webs. There are a few ways of doing this despite what the engineering above might think. However, the easiest way to do this might be to cut rectangular pieces of 1/16" balsa that are applied grain vertical to the back of the spars in between the ribs. It is important that the webs are snug and fully bonded to the ribs and spars. Because the wing has a constant chord and thickness, these shear webs are all identical. You can cut them a tad proud of the spars and then sand them down flush with the spars prior to sheeting the LE and center section. The last thing you might want to "build" on the model is the application of the cross grain fuse rear bottom. Finish the entire airframe, install all the gear and then, when you are sure that everything fits and is working, you can take the 1/8" sheet and apply it in sections from front to back cross grain across the fuse bottom.

Oh, the strakes are the sections of stab that extent forward and join the stab with the fuse top. it is easier to install these after the stab has been aligned and mounted permanently. Do this with the fuse inverted on a flat table top with the wing aligned and permanently mounted first.

I hope this rather lengthy breakdown helps.

David.

Wow! Thanks David, that was awesome.

I will be printing out your recommendations to compliment the plans.

Thanks again,
Ian (you were right...congrats )

Here are some pictures of a radio installation that might be a little more appropriate for your glow model (standard servos are used since this is a 40 size model). You can see how I went about planning it and then changing things as it went together. I needed to make sure the area behind the wing LE former was able to be cleared so I could remove the fuel tank if needed. This particular model doesn't have a front tank bay hatch like the SP.

I should mention that here the servos' are installed in a staggered fashion because the elevators are independent (not joined) and operated by a forked pushrod from the single rearward servo. In front of that servo is the rudder servo which is centered on the fuse center-line and used with a Pull-Pull wire setup rather than a pushrod. In your case, using two pushrods, you can simply install the servos for the elevator and rudder side by each in the back with the throttle servo just forward of them as described in the post above. Very similar to what I did on the SP but it might help to cut a servo tray on which you can mount the receiver -especially if it is a small modern 2.4 GHz type Rx which is hard to pack in foam.

I mount my receivers by using double sided foam tape on a little lite-ply board which in turn is velcro'd to the radio tray or fuse side. This helps to insulate them from vibration. One can also use a velcro strap with the Rx backed by a piece of foam rubber but they have been known to slip on occasion from under the strap.

David.

Ian,

glad it was helpful.

David.

That is a very, very, very nice installation David. I was looking into light balsa and laminating it with CF for the Tiger Tail III, but I kept looking back at the 1/8 ply trays I used to hack and saw up back in the day. Did you use 1/16, 1/8, etc? I was thinking of using basswood to save a few grams or simply the 1/8 ply with lightening holes, on rails.
hook

Well thanks Hook,

I'd like to bask in the glory of it but there wasn't too much rocket science behind it. CF laminated balsa is very cool and stiff but also a little pricey (well, CF is). If you are going to produce some for formers or some such, then by all means, might as well make a servo tray while you're at it. Otherwise, good old fashioned hardwood (basswood or ply) does the trick. Provided the try is properly supported, I find that 1/16" ply is fine but if I had more of it, I might use 1/8" lite ply on larger models. The lite ply can be a little dangerous though as it can "chip". I made the frame for this model with 1/16" ply and then, where the servo's go, I back up the tray (above or below as required) with some 1/8" ply or square hardwood stock. Even if using 1/8" ply, I find it is not thick enough to adequately capture the servo screws.

I am still on a search for the ultimate way to mount an elevator servo sideways though in the absence of a purpose built side mount servo. Putting the servo on it's side is really the way to go in my opinion with forked split elevators - almost completely linear motion is transferred to them. I often find that there is not enough space between the fuse centerline and side to accommodate a standard size servo and put the output on the centerline. With classics, I've found that I need to use low profile aileron type servos so they will fit.

I'd say go with the 1/8" stuff on your TT and remove material where not needed - more effective on a 60 size model.

David.

David, my plane weighs 3 lb 2 oz ready to fly. The OS 25 is an older plain bearing engine, it has more than enough power for the plane, my reason for liking the ST23 would be that it idles much better than the 25. I did not put the strakes on and it does not seem to detract from it's flying. putting up some pictures of my plane.

Very cool Ed!

Those do look like some vintage servos! There's something nostalgic about building a 30-40 year old design with radio gear that is of a similar period. Unfortunately I parted with most of my vintage radio gear while still a kid. Back then, it was of course not vintage gear. I was particularly fond of some little Futaba S20 servos that I had - miniature and expensive by the standards backs then. I build many a small model with those servos.

Replied to your PM.

Ian, by the way, Ed's 50 oz SP sounds like a very respectable AUW for a stock glow version. I'm actually wondering if my 40 oz version will fly more like a glider than a little pattern plane!

David.

Thanks David, the servos and radio is my Ace Silver Seven, works excellent, plus the servos are small

got your PM

I learned how to build light and strong from my days of racing QM15, 2 1/2 lbs total weight 1 lb of plane and 1 1/2 lbs of gear.it helps when building as you sort of know what is too much as far as adding weight and not being of benefit.

I might have of of these Super Pacer kits for sale if anyone is interested.

Thanks,
paul