mmattockx

Bored at work and looking to entertain myself with interesting thoughts...

If a person was looking to break the 150mph barrier, what is the easiest, cheapest combo to get you there? I realize it's not that easy, but some ways are easier than others...My initial guess would be a composite Q500 with Jett 60LX turning a smallish 8" or 9" pitch prop at around 19-20,000rpm. Maybe clip the wings a bit to help out. Should be relatively easy to fly, the engine runs well and throttles nicely and it is all over the counter stuff, no muss, no fuss.

Yes / no? Other combos that would do it for less?


Mark

HighPlains

My Feedback: (1)

150 with a quickie is easy. Any used (but not used up) Nelson or Jett racing engine on about any quickie will do it, been doing it for over a decade. Nothing to it.

Aim higher, there is going to be a FLOOD of Q40 engines dumped on the used market, buy one and build a Q40 airframe and you can easily go into 180-190 mph region. A 5 mph advantage means the world in racing, but for sport flying just lower the nose on the next pass.

150 on the cheap, go with the quickie, clean it up slightly, and put a Nelson or Jett pipe on a good .45 with a racing prop clipped down slightly.

bob27s

My Feedback: (19)

A good composite bird like a Bird of Prey with a 60LX will be as fast, or faster, than a competitive 428 racing plane - easily over 160 mph. Turns the crud out of a 8.8x9 prop without effort.

Same engine in a QM40 airframe will go quite a bit quicker too.

THe used engine market is something to keep in mind, especially if there is a wholesale lot of Q40 engine hitting the auction blocks. Easy enough to run if you dont mind no throttle.

Bob

daven

My Feedback: (1)

There are big claims about the new nelson LS Qm 40 motor that debuts next week. If the claims are true, there will be a flood of the older motors available. Not cheap, but I would guess you would be able to find a good one in the $200 range. These engines won't be worn out, just not as competitive. There were 3-4 sold last week and 3-4 listed right now on the Auction site.

Even a $110 Viper with a sport jett .40/.46/.50 will surpass 150 mph.

mmattockx

See, now that is the answer I was really looking for. I have a Dominator 500 waiting to be built that I will keep this in mind for when the ST45 gets too dull for my taste. One quick swap to a Jett 50 or 60LX and I will be out of control again...

Thanks, Dave.


Mark

daven

My Feedback: (1)

The dominator with a Jett will get you there. I flew a dominator at the 2000 nats.

combatpigg

My Feedback: (3)

A Diamond Dust with a Webra .50 will do it. 9x8 prop and open header.

HighPlains

My Feedback: (1)

Put enough power on a toilet seat lid, and it will do 150.

proptop

My Feedback: (8)

Would that be a wood, or plastic toilet seat Bob?

P.S. I got the props...you have a PM

colbourne

Or put enough lead in a glider and it will do the same.
I think it is fun using the same engine and trying to make better cleaner aircraft, pipes , props etc.

mmattockx

Bob,

My thoughts were an easy to handle and tune sport set up, just a REALLY fast one. So a lack of throttle would be a serious issue to me. You and Dave have sorted things, though. If all I need to do is strap a Jett 50 or 60 on the nose of my Dominator when I feel the need for more, that is a slam dunk. Affordable (sort of, a $300-$350 50/60 is still hard for me to adjust to), easy to operate, easy to fly and more than fast enough for my needs, that is a great combo.

Anything I should do to the Dominator while building it, just in case I do go buy a 60LX one day? Any reinforcements, servo/linkage choices, carbon fabric under the wing skins while sheeting it, etc?


Thanks,
Mark

daven

My Feedback: (1)

Mods I would make to the Dominator would be:

1/8" carbon fiber push rods from www.darrolcady.com

Heavy Duty Aileron Torque rods (I believe sold by Dubro)

I wouldn't use carbon Fabric under the skins, but I would use at least a 1" strip (top and bottom) of .007 carbon laminate on the highpoint of the wing.

I believe the firewall is 1/4" thick. I would glue a 1/8" piece of aircraft ply on the front of the existing firewall tying the fuse sides and the firewall together.

Make a slurry of chopped carbon and epoxy and fillet the inside joints of the nose around the firewall (carefull of the blind nuts).

Personally, I would stick with the Conventional tail. Easier to build and you won't give up any noticeable speed.

I would glass the plane with 3/4oz glass and paint, as opposed to plastic covering.

Its been a few years since I built one, but if you have any specific questions let us know and I'm sure we can help you out.

Clean

Had Salmonella once, you're right!

Oh, and do I need to mention the BullDawg again?



[link=http://www.spssalesinc.com/downloads/BULLDAWG%20CORO%20PLANS.pdf]Coro Details[/link], [link=http://www.spssalesinc.com/downloads/BULLDAWG%20FUSELAGE.pdf]Fuse Details[/link]

Not Quite a Toilet seat, but close.

bob27s

My Feedback: (19)

Yep, no problem with the Dominator....

The kit-built or plans built Q-500 designs can handle pretty much any engine. At least you know how its build and can build it to suite the application.

I tend to urge caution when trying to use a 60LX or Q-500 428 engine on one of the ARFs.... you can fly them with this power, but some careful attention to details is required.

also a suggestion, email [email protected] and request the HANGAR SALE list.

Bob

mmattockx

Thanks, Dave. Good info here.

I had planned on the heavy duty torque rods and I am going to try the epoxy bushing method on these as well. I will make sure there is a strip of carbon for the spar and I may still use 0.5oz carbon mat under the skins, just to make me feel better. The weight gain is almost unmeasurable for the extra security I will feel...

Is the epoxy/carbon mix any better than hard tri stock for reinforcing the firewall/fuse joints?

I was thinking of the conventional tail, too. Just a little easier to get straight and I am sure I won't notice the difference in performance.

I was also thinking of trying the PolyCryllic and 0.5oz glass method for finishing, so I will definitely do it instead of film. I much prefer the look and toughness of the paint finishes to film, so this is an easy choice to make.


Mark

bob27s

My Feedback: (19)

Yeah, what Dave said Stick with the conventional tail - flys great- easy to set up .

I typically go with iron-on covering on the wood planes. Personal choice.

One thing I always add is a 2oz fiberglass-cross over the outside of the complted firewall - reinforces the front end. Also, you do not want a hatch - you want the front end as stiff as possible.

Using a bubble-jett or tetra tank is absolutely necessary if running a 428 engine, or one of the sport-jett engines.

daven

My Feedback: (1)

Tri stock would be fine also, if the plans ask for a hatch for the tank, don't do it. Just glue the nose up tight, that is where you want the plane the stiffest to help transfer power back through the airframe. Bobs suggestion of glassing the nose is a good one also.

Poly works fine, I use epoxy since I buy it by the gallon. I believe epoxy is harder, stiffer, and stronger than poly but in your application it will be just fine.

Definately check Dubbs Hangar sale. Don't think you need a BSE engine to go fast, the cast case Jetts are just fine and can be had a considerably less expensive pricing. The BSE engines look awesome, but don't offer that much more performance (if any).

Also, definately plan on a bladder tank like Bob suggested. Your engine will thank you for it, and you won't have to worry about bubbles which can cause your engine to go lean.

I wrote a series of speed secrets a couple years ago and they are a "sticky" in the pylon general discussion forums. You may want to read through those for tips as most of them apply to quickie type airplanes.

mmattockx

Dave & Bob,

Thanks again for the advice, it is most helpful.

I was going to mention the fiberglass cross on the nose, forgot. 2oz glass is OK for this, or heavier?

You are right on with the PolyC, it is not as hard as the epoxy, but it will hold the cloth just fine. It is a bit more subsceptible to hangar rash compared to the epoxy, but vastly tougher than film.

I will have to look at the plans to check on the hatch, I don't think it has one shown, though. I need to look at the tank situation, too. I would like to keep a standard clunk tank with the ST45 on it, but I want to be sure I can switch to the bladder type if/when I want to add the Jett engine.

I will check out that sticky thread for more info.


Mark

vasek

My Feedback: (4)

put the toilet (seat) a mile away > eat some mexican Chili and soon enough YOU'll be doing 150 MPH

bob27s

My Feedback: (19)

2oz at a minimum. I usually lay up the center sections of my wings with 3 layers of 2oz cloth, so I have pieces laying around to use for the firewall.

Quick method on this.....
Obtain four large, round, rubber balloons - 9" size or larger works well.
Blow it up once or twice - just to get it loose.
Sit down in a chair. Put the fuselage between your legs, firewall pointed up.
Take the inflated balloon - and push it over the firewall, quickly, as you let the air out - dont pop it.
(this is why you need 4, just in case)
The idea here is for the balloon to stretch over and collapse over the front of the fuselage, like a reverse vacuum bag.
Once you have that technique figured out, so the balloon does not come sliding back off....
Place the fiberglass cross in position .... make sure it fits.....
If you have the firewall pushrod hole, blindnuts and inserts installed (you should by this point) fill the holes with clay or wax.
Wet the cross down with epoxy (I suggest 30 minute type or finishing epoxy)
Position the cross on the firewall. Flatten the cross tabs against the fuselage sides, top and bottom.
Generally even out the epoxy - not a big deal - just get it close.
Then...... the moment of truth.....
Inflate the balloon - and force it down over the nose of the plane (as you practiced).
Let the epoxy cure over night ...
When you remove the balloon, you will have a nice, even, smooth surface, and an excellent bond.
Only requires a light sanding.
Then you can open up where the bolt holes and throttle pushrod locations are

As with Dave, I recommend epoxy for all of the glass work. PolyU is nice, but this is not for finish looks only - it is structural reinforcement, and the stiffness of glass/epoxy is beyond that of polyU/epoxy.

mmattockx

Bob,

Speaking of glassing center sections, when you use multiple layers of different width (as I think you are saying you do), do you put the widest down first and then work to the narrowest one or the other way around?


Mark

bob27s

My Feedback: (19)

my prefered method .... bottom strip (first layer down) is the narrow one

MJD

My Feedback: (1)

Interesting method. Have you tried a condom yet? (on the airplane)

I use a variation of this on wing center sections - I have a bunch of old crap heat shrink covering lying around such as pale blue solarfilm and the like (great choice for visibility.. not!) - it has a better use now. I take a wide strip of covering that will go completely around the center of the wing with an inch or so of overlap, and that extends an inch or so spanwise beyond the area to be glassed. I then lay up the glass, making sure it is wetted out reasonably well. Next I wrap the glassed section in the covering, adhesive side out, not in, and tack it to itself at the overlap attempting to keep it reasonably wrinkle free. Then comes the heat gun, and I shrink the covering over the center of the wing. The cool thing is that the heat reduces the epoxy viscosity greatly, and the epoxy distributes itself pretty evenly throughout the layup, and as I am sure you can guess the covering acts like a vacuum bag and holds everyhting down. Don;t overdo the heat, and yes if you use too quick a curing epoxy you could start it gelling prematurely with too much. But I have not had any problems - moderate heat simply accelerates the cure reaction, it does not deteriorate the epoxy. Once cured overnight, the covering peels away leaving a pretty decent surface. Not perfect as a vacuum bag, but decent, and a touch up with sandpaper usually finishes the job nicely. Done this several times and like the results.

MJD

HighPlains

My Feedback: (1)

Assuming you are going to sand the glass before painting or covering with plastic film, I think it is better to place the widest glass on first, progressing to the smallest. That way, you do not risk sanding through the glass at the edges of pieces below. Here is a photo of the glass outlined on top and bottom of a destroyed wing (mid-airs suck). I use polyester resin, and cover it with wax paper which allows the resin to assume the shape and smoothness of the wax paper (locally stiff, globally flexable), so there is little to no sanding required. Just work out the air between the glass/resin and the paper. Use the paper only once or you will find out why.