Just got a PT 19

My first thought was the 'ol brass tubing and JB welded in place repair, but after reading the post by Marleysky i think that would work just as good and a lot quicker. You could also locate a firewall for a babe bee and use a babe bee engine w/ tank instead. Mid late 70's pt-19 were made with both.

Mark Boesen wrote:My first thought was the 'ol brass tubing and JB welded in place repair, but after reading the post by Marleysky i think that would work just as good and a lot quicker. You could also locate a firewall for a babe bee and use a babe bee engine w/ tank instead. Mid late 70's pt-19 were made with both.

Thanks for the tip on the fuel tank repair. Swapping firewalls and engines is a possibility too. My first PT19 had a Babe Bee in it. Could the engine that's in my current PT be converted to use an old style engine mounted tank? Or is that not possible?

yes, but you'll need the babe bee firewall.

WELCOME TO THE FORUM TLAnderson !! If you have a small engine shop with in distance from you there are small nipple connectors they use on some brands that push into the right sized hole and seal well with a bit of fuel hose around then , Brands like Ryobi , Homelite and Poland used them and should not bee hard to get . Just a thought , Eric

Some advice on flying your small models. The handle pictured here has "too-wide" of a line-spacing.



Ideally.. you want your handle's line-spacing to be equal to the spacing of the lead-out holes used in the model's bellcrank.. which will result in a 1:1 ratio. You can make your own handle with this in mind.. or buy one that has multiple holes to choose from. It will be easier to control your model.. because your control inputs will be less sensitive.

The tank on my PT19 is a translucent/white "bowl" that I've had problems with coming unattached.



This "old" fuse shows the tank in place..



I've glued it back on.. but I think it originally was supposed to be a "snap-fit". A new bowl would not snap on either.. so I figure that the mount on the fuse is worn.

Your tank may be a snap-fit too.. but it's the first one I've seen of that type. If you can (easily) pop it off.. you can make a nipple from a small flared lead-out tube installed from the inside. Open up the hole to tightly fit the tube and use small-size silicone tubing cinched-up tight.. to hold it in place. Reinstall the tank and you'll have a more "original-looking" repair that is un-noticeable.



Another option is installing a small wedge-tank like this one.



You'd need to extend the fill/vent up-through a hole drilled in the top of the fuse; using either a soldered-on piece of brass/copper tubing.. or a short length of silicone tubing having a nipple pressed into it for filling. Attach the tank's flat side to the "inboard-side" of the fuse using double-sided tape after cleaning the mating-surfaces with rubbing alcohol to ensure good adhesion. It might stay in place for many a flight. If it comes loose.. clean again and re-stick.

Good luck getting the Testors engines running again.. and don't forget about the handle's line-spacing!

Good advice Roddie I had forgot the tank would unsnap , I haven't seen one of these models in a long time , Also there are some threads here on cleaning and running Tester engine just do a search // You know the Gray RTV would probably hold your tank back in and seal too ,, .. https://www.permatex.com/products/gasketing/ultra-series-gasket-makers/permatex-ultra-grey-rigid-high-torque-rtv-silicone-gasket-maker/ Eric

Thanks for all the great replies. I'm not sure if the tank is removable. I'll look at that closer.

Something else I was wondering about is fuel. No one around here stocks 25% nitro fuel with castor oil in it. I was wondering if castor oil could be added to the fuel that's available around here. I assume castor oil would be available at a pharmacy.

Pharmacy Castor oil will work but is probably not your best choice.  Brodak sell the right stuff in pint & quart bottles, and I think they can post it.  http://brodak.com/castor-oil-quart.html
Sig as well.  http://www.sigmfg.com/cgi-bin/dpsmart.exe/MainMenuFV4.html?E+Sig
Don't be too worried about 25% nitro.  15% is quite adequate and you will notice very little difference in performance.

Rod.

If you don't have fuel at this point I would suggest going with these people good fuel decent price and you may want to get something to go with it + the shipping is less expensive than others up to 4 qts. for the same price I think is the way it goes . http://www.sigmfg.com/cgi-bin/dpsmart.exe/IndexAircraftAccessoriesF.html?E+Sig ,,, the Hazemat charge comes in on GAL.s Eric

Oldenginerod wrote:...Don't be too worried about 25% nitro.  15% is quite adequate and you will notice very little difference in performance.

Rod.

Rod I have different results than you and I don't know why. In my experience with two fuels of 10% nitro difference, I have found that the higher nitro of the two makes a noticeable improvement, both in ease of cranking(with small props) and engine stability and usually top speed after unloading in the air. My two would be 25 and 35%. I admittedly don't always lower the compression for higher Nitro fuels. I do fly Cox 1/2A more in our 7 warm months, say 80-102F(I stay home when it's hotter than that), and I think you may have a longer warmer season. So based on temp alone, that makes my comparison more contradictory.

I can't come up with any idea why we should have differing results I use med. hot plugs year round. I remember the first time I instantly noticed the difference, in my .049 Stuka when I was a kid and bought my first red can of Cox fuel. If we both flew in cold weather I might expect less of a performance difference, but for us both flying in the heat, my big change compared to your small change seems to me to make less sense. Maybe I should change compression with temp more thoughtfully than I do. This would be a good question for Randy.

Or maybe it's too close to bed time for me to be thinking so hard about this topic. This is when I usually say stupid stuff and am horrified to read it in the morning.
YawwRustynnnn

Got 'er in the air tonight.  Got two flights in.



Last time I flew a PT 19, it was 1971.

I fixed the fuel tank by super gluing a 1/8" nylon hose barb into the hole, after drilling it out slightly larger. The tank was also cracked so I coated it with some miracle liquid plastic stuff that the wife found on one of her shopping trips. Seems to work, the tank doesn't leak.



For fuel, the only thing available locally, is Traxxas Top Fuel 20% nitro. States right on the label that it's not for airplane engines. I assume that's because there's not enough oil in it. I bought a quart of it. I had 8 ounces of the same brand fuel, but 33% nitro, so I mixed the 8 ounces of 33% with 8 ounces of the 20%, and 4 ounces of drug store castor oil. The .049 seems to run fine on it, and it slobbers oil all over the airplane just like the old Cox fuel used to do. If this is a really bad idea, please say so, but the engine seems to like it.

The only other issue that the plane has is that the firewall seems loose in the thrust angle adjusting grooves in the fuselage. It's really easy to move from one groove to another. Thought about building up the top of the firewall with JB weld or something to get it tighter in the grooves. Anyone run into this before?

One other thing I was thinking of was putting larger diameter wheels on it, so it would handle rough surfaces better. It didn't really like the gravel runway I was using tonight.

Thanks for all the tips so far. It was really fun to get that bird in the air.

That's an awful lot of oil by my reckoning. 8oz+8oz+4oz=20oz. The added 4oz of oil makes 20% added to whatever is already in the fuel, maybe around 15%. That's 2.4oz of oil in the 16oz of fuel prior to adding castor. So 4oz+2.4oz=6.4oz. That's 31.25% total oil, assuming that my assumption of 15% in the Traxxas fuel is about right. Won't hurt it, but it will be messy. Actually, apart from the mess it would probably be a pretty good blend. (Happy to have people challenge my Maths, or Math to most of you Statesiders)

Rod.

TLAnderson wrote:Got 'er in the air tonight.  Got two flights in.



Last time I flew a PT 19, it was 1971.


Thanks for all the tips so far. It was really fun to get that bird in the air.

Congrats on the flight!!!  I like stuff like this: getting some new flight time after a long break. Good luck on your future flights AND WELCOME to the FORUM!!!!

Oldenginerod wrote:That's an awful lot of oil by my reckoning. 8oz+8oz+4oz=20oz.  The added 4oz of oil makes 20% added to whatever is already in the fuel, maybe around 15%.  That's 2.4oz of oil in the 16oz of fuel prior to adding castor.  So 4oz+2.4oz=6.4oz.  That's 31.25% total oil, assuming that my assumption of 15% in the Traxxas fuel is about right.  Won't hurt it, but it will be messy.   Actually, apart from the mess it would probably be a pretty good blend.  (Happy to have people challenge my Maths, or Math to most of you Statesiders)

Rod.

Yes, I disregarded the oil content of the fuel. The label doesn't say how much oil is in it. I assumed about 10%. Hopefully, I'll get some fuel from SIG or Brodak soon, but I needed something to run the engine, so I figured I'd try this. Worked real well. The engine started easily, and ran well.

Kim wrote:

Congrats on the flight!!!  I like stuff like this: getting some new flight time after a long break.  Good luck on your future flights AND WELCOME to the FORUM!!!!

Thanks. Looking forward to learning how to fly it. Summers are short up here, so I need to get the flight time ASAP.

TLAnderson wrote:

Kim wrote:

Congrats on the flight!!!  I like stuff like this: getting some new flight time after a long break.  Good luck on your future flights AND WELCOME to the FORUM!!!!

Thanks. Looking forward to learning how to fly it. Summers are short up here, so I need to get the flight time ASAP.

Man, I'd sure consider (and admittedly, this IS coming from some who has never mixed their own fuel) getting some 25% Fitz Fuel or Sig, sticking a 5-3 prop on that puppy and logging a bunch of time while the sun shines !!!

You could still do fuel testing as the flying continues...

Was attempting a takeoff tonight on a rough field, and broke the prop. I think it hit a rock. Cracked the nose from the engine jumping around with the blade missing. I put some larger wheels on it thinking it might roll easier on rough ground, and give the prop more clearance. Guess I need to find a smoother runway.



The prop is left handed. They seem kind of rare. Would those three blade 5" x 3.5 pitch left handed props work that Cox International is selling?

http://coxengines.ca/cox-.049-propeller-left-hand-pusher-5-x-3.5.html

Yeah, the PT won't jump into the air without a rollout. Some light but fatter wheels might help.
After I put a Killer Bee with a 5.25x3 prop in mine, it would leap into the air without a rollout.

TLAnderson wrote:............
The prop is left handed. They seem kind of rare. Would those three blade 5" x 3.5 pitch left handed props work that Cox International is selling?

http://coxengines.ca/cox-.049-propeller-left-hand-pusher-5-x-3.5.html

Welcome to the forum..

I believe a left-handed prop may have an issue in forcing a C/L plane too much to the right (in counter-clockwise flight direction). Right handed props do the opposite, hence, among other reasons, is the rudder in C/L planes permanently set a bit to the right, see your photo on the PT that was I guess originally equipped with a right-hand prop..

In R/C planes this impact of right-handed props is often balanced by off-setting the engine shaft  by 2-4 degrees to the right so that the prop thrust thus pulling the plane a bit to the right and the aerodynamic forces of rotating airflow from the prop,  pushing on the tail of the plane to a left-oriented flight path, be balanced.

I guess your PT will fly even with a left-handed prop, but will want to break out from the circle, keeping its nose much too outward...maybe you should get a normal right-handed prop and the matching starter spring, both sold by COX Int'l..Reed valve engines will run in both rotation directions equally well.

The "pusher" prop of COX Int'l is  left-handed simply because it is intended for pushing rather than pulling the vehicle (see the Shrike model of COX), while in right-hand rotation. This will not be running efficient in left hand rotation because the airfoil of the blades will turn in the direction opposite to its intended use.

Nice wheels! I did the same with my PT-19.. but chose to also make new gear-struts that are a bit longer. (note that I also have a crack in the nose. The material is pretty thin in that area..)



The original gear's axles (on mine) are crimped to hold the wheels on.. (another reason I chose to make new legs..)



Here's the new gear, with "Sig" 1.375" diameter wheels, precision-washers and spring-collar retainers. I'm sure that your new larger wheels roll much smoother too!



Your model's issue with the engine-pitch notches seems strange. I've replaced my fuse once.. but both fuses held the engine-position fairly tight. Check to see if the top off your engine-mount has a sharp-edge where it contacts the notches. It may be blunt or "rounded".. which would allow it to slip-back to the "expert" setting with any pressure (landing) on the gear. You could try a few swipes with a rat-tail file where the mount "pegs" fit into the fuse, which would allow the top of the mount to bear more on those notches. Make sure that the rubber-bands are tight in this area too.

Good to hear of your fuel test-mix! As for props.. a L/H "is" desirable.. because it helps with line-tension. My PT-19 has no outboard tip-weight. (I'm guessing that none of them did..) I was lucky enough to find some NOS Cox black 6" x 2" L/H props from an old hobby shop that was closing a few years ago. That said; I have flown mine with R/H props without any trouble. You might want to try a 6" x 3" R/H.. now that you have more ground-clearance. Just to be safe.. tape a quarter-dollar or similar weight steel flat-washer to the under-side of the out-board wingtip.

Most of the people here are flying 1/2A sport using braided "Spectra/Dynema" 20# fishing-line, utilizing "Palomar-knots" at the terminations. I haven't personally flown with that type of line yet.. but it's said to be a LOT less draggy than Dacron.. until it gets oil-soaked. That would take a while though.. and can be lessened by wiping your hands with a clean rag before handling your lines.

Wishing you continued success.. and happy flying!

Great to hear you got a couple flights in if you order some stuff from Bernie at Cox Inter. I would suggest this prop for RT hand ,, and you may consider a cardboard box runway there are other potable TO strips you can use a few here bring there own ( I flight in the back yard ,kinda, have a Alum. sigh as a strip ) But back to the prop If you put a comment in that you would like some of there 5-3 LH NEED TO BE BOILED BEFORE USE Props they may send you 2-3 !!?? This Rubber Ducky... Right hand spring also ..  http://coxengines.ca/cox-.049-propeller-5-x-3-safety-tip-yellow.html,,,,,,,  http://coxengines.ca/cox-.049-snap-starter-spring-no-drag.html  Happy Landings !!

Pretty certain the 6X2 LH prop is standard original fitment on some model PT-19s.

Hi again! Hope you got a few more flights in. I'm not sure if you mentioned having any extra props. I should mention (following-up my last post..) that I flew my PT-19 on 25' lines, which was dictated by the size of my flying area at the time. It may well be best to purchase a few of Cox International's 5" x 3.5" L/H props to try. As I said; I've used 6" x 3" R/H props.. (without adding tip-weight..) but flying with longer lines might be a bit more "sketchy". This airplane is a flight-trainer.. and the 6" x 2" L/H that it was designed to use; actually torque-rolls the model to the "right".. which really helps if a breeze blows-in. The model will be less likely to lift the outboard wing and come in on you. This is a BIG advantage to running reed-valve engines on small models.. because of their ability to run equally well in either direction.

My PT-19 came with the "zero-drag" L/H starter-spring.. as yours has. These are hard to find. Make sure that you keep track of it when and if you remove the engine from the model. It's not a part that would ordinarily be removed.. unless you chose to run a R/H prop and starter-spring. Keep it with your spare-parts! It's one of those parts that you'll want to have when you need it.

If you get the urge to fly without a pit-man.. you can make a simple "pin-stooge". The PT-19 has a tail-skid that affords a point to accept a stooge-pin.



A pin-stooge is easy to make! Take a look at these photos. The "pull-chord" runs out to your handle (line-length).




The "pin" holds the model (engine-running..) until you grab your handle and pull the chord to release it. You should have no trouble with roll-out (ROG) with those big wheels.. even on short-cut grass! There's nothing more satisfying.. than a nice rolling take-off to start your flight! It gives you some time to gain some composure... and ease it on up to about 5-6 feet, and level-out.