GP Dazzler & Engine selection
 

Just finished my GP Easy Sport, and while I will probably spend the entire season flying this plane, I already have my next project on the workbench (yes I'm addicted :D ) : a Great Planes Dazzler.

Now, the mfg suggest the use of an OS .40LA, and specifies a weight of 3,5 - 4 lbs.

I'm planning on building this thing as lite as possible: I will replace all balsa sheeting from the kit with competition grade balsa handpicked from the LHS. I'm also planning on replacing a lot of the plywood with balsa and laminating a thin layer of fiberglass/carbon in between for strength. I'm definetely aiming for the 3,5 lbs margin, or - if at all possible - even slightly less than that.

Now I have an OS .46LA in my workshop, which crancks out 1.2Bhp @ 16000rpm, compared to the 1.0Bhp @ 16000rpm of the .40LA
The best part of this is that the .40LA weights 9,5oz and the .46LA only 9,6oz - which is quiet the same...
They also have the same outside dimensions (they actually use the same housing) so mounting won't be any issue.

Now, what I'm wondering, will it have good vertical ? Can I make it hover, or it the engine just not up to that job ?

the .46LA is now in a trainer plane weighting in at 5 lbs, and a 67" wingspan (the dazzler only has a 48" WS) It doesn't have unlimited vertical, however there enough power for most things (yes it can pull a hammerhead if I pick up enough speed on the horizontal line... sort of)

On the trainer I had an APC 11x7 prop, which I will replace on the dazzler with a 11x5 (this should already improve vertical right ?)

Any suggestions welcome ! If anyone has already build the kit and has some good tips, I'm listening !

GP Dazzler & Engine selection
 

OK. Seems like nobody has any experience with this combo.

Let's rephrase. Let me what kind of engine you have put up in your Dazzler, the prop you used, and what the vertical performance was.

I'll do the maths myself!

GP Dazzler & Engine selection
 

Dazzler_BE:

I am not a fan of the LA series engines. Leave the 46 on the trainer. Buy a Magnum XLS 46 for the Dazzler, or an OS 46 FX. Except for the price, they're the same engine.

The OS 46 FX, with a 12.25x3.75 APC will haul my Magic vertically out of my hand. It should do the same for your Dazzler.

Bill.

GP Dazzler & Engine selection
 

Hi Dazzler,
It looks like we are sailling in the same boat. I also have a Dazzler which is just completed. I have not flown, but another friend who just build it and has a 40 LA is not that great a performance.

I would suggest you go in for a 46 FX with a 11X 7 prop that would be the best unlimited vertical trust me. LA cant beat it.


Sharad

GP Dazzler & Engine selection
 

The FX.46 does weight 4oz more than the LA.46 Hope that's not a problem ?

Anyway, I will still have to start contruction, so I'm not flying it for the next couple of weeks.

Please keep me posted on any experience with the FX.46

I currently have one in my Easy Sport, I could always try it, but I don't like to swap/build over engines

Is a 11x5 of 12x4 prop not better for vertical performance compared to the 11x7 ? I was always told that higher pitch increased top speed at level flight, but lower pitch increased thrust (in vertical or manouvers)

GP Dazzler & Engine selection
 

I was thinking about building a Dazzler but don't know which engine to use. I already have a Irvine .53 lying around and thought about using that. Will that be ok or will it be overpowered?

GP Dazzler & Engine selection
 

Actually, the mfg calls for a .32 to .40 2-stroke, so an OS .46FX would actually already be "overpowered"

So I think an Irvine .53, putting out a 1.7Bhp might be a bit to much... remember this is a very small, light plane.

Anyway, if you decide to build one, let me know !

I already read some articles on structural weakness in the kit, that must be reinforced (for which purpose I will use carbonfiber/epoxy)

The GreatPlanes prototype has an OS.40 LA inside, but this will be underpowered for vertical I'm sure. Apparently even a .46LA doesn't pull it.

So perhaps an OS.40FX or .46FX are good, let's wait and see what SHARADEDGE540 's experiences are...

GP Dazzler & Engine selection
 

Yes, a 11x5 or 12x4 will be better for vertical. Lower pitch does not increase thrust, but your engine will be able to turn the same diameter prop with a lower pitch faster than one with a higher pitch. The higher rpm at the same diameter is where you get your higher thrust. Also, if you increase diameter and can spin the prop at close to the same rpms, ie 12x4, you will increase thrust.

You might think about going to a smaller load prop on your trainer as well. A 11x5 on your trainer would definitely improve your hammerhead. :) You would most likely also see an improvement in throttle response, which is very nice to have to get out of bad situations while you are learning.

Good luck.
bsc

GP Dazzler & Engine selection
 

Hi,
I will be having my radio which has gone for repairs to the futaba service center, in a weeks time. I would be able to coment on that after then only.

As per the 4 oz weight is conserned I dont see any problem as 46 FX has more power then the 46 LA. Any way lets do experimenting with our engines and props.

I am not bit sure if we can go with 12X5 prop. on the 46 FX.

Thanks

Sharad

GP Dazzler & Engine selection
 

Sharad:

Almost everyone who has experimented with the props has settled on the APC 12.5x3.75 as the best for the OS 46 FX pulling a 3D plane.

Bill.

GP Dazzler & Engine selection
 

I have the Tower hobbies Uproar which is nearly identical to the Dazzler except for the omission of the turtle deck. The OS 46FX with a 12.25x3.75 APC is the best combination for this plane, IMHO. Yes the FX weighs slightly more than the LA, but it makes much more power and is a better all around engine design, hence the $48.00 increase in price. To me the extra cost is more than justified by the performance gain and longevity if properly cared for. Another good engine for this plane would be the Thunder Tiger 46 which is a little less expensive, but a good engine none the less.

If you have already mastered your Easysport I think you will have no problem flying the Dazzler, if that is a concern. It's an easy flier. The Dazzler is a tail-dragger, but should not pose much of a problem compared to the Easysport because it doesn't stay on the ground long on take-off.

As far as building goes, there is not a lot of plywood in the kit and it builds light per the plan, so personally I think it's overkill to replace it with balsa laminated with fiberglass as you suggested.

I enlarged the control surfaces on mine and added counterbalances to the elevator and rudder, while making the horizontal and vertical stabilizers 1/2" smaller across the chord of each. I didn't like the way the vertical stabilizer was mounted either, so I mocked the mounting of my GP Cap 232 vertical fin. The one thing I would recommend is to not drill your engine mount until you have the plane complete. This way you can adjust your CG by moving the engine for or aft as needed.

Have fun!

GP Dazzler & Engine selection
 

I started building in the meanwhile, and found out that this indeed a very lightweigth kit. Compared to other GP kits, were some balsa is of some really dubious quality and not very consistent, this kit has all the best light grade balse throughout!

I will however reinforce the fuselage sides above and below the wing, as there is only about 0.35" of balsa on either side, making is very weak at that point. There's no ply doublers, just balsa doublers, and I feel laminating some fiberglass in between them would make for a much stronger plane, while adding almost no weight...

GP Dazzler & Engine selection
 

I have a GP Dazzler kit, which I will be building later in the year. I'm planning on using an Irvine 39 it in. I'm not sure whether these are available in Belgium, but they are gaining popularity over here - 25 sized engine, puts out more power than an Irvine 40. I currently run one in a Flair CAP230, and it will pull unlimited vertical with a 10.5 x 6 Bolly prop. It has never missed a beat since day one, and I have only ever had a deadstick when I ran out of fuel. It is a very classy engine.

GP Dazzler & Engine selection
 

I just sold my dazzler. I had the arf version and was not getting unlimited with a os46fx 12.25 x 3.75 apc prop ( new engine running rich for break in). It is a nice plane, however, may I make a suggestion?
The wire landing gear that came with the arf was junk. It was very springy and the os46fx put enough weight on it to spread it out after 1 or2 landings. After that I only had 1/2" clearance between my prop and the ground. Kind of a pain when taxiing caused grass stains all over. Anyhow. If the kit comes with the same gear I would recommend you replace it with something better. Other than that, flys great,looks great. Enjoy.

GP Dazzler & Engine selection
 

WOW!!! It is good to see someone else who is moving to the dazzler from the EASY SPORT. They are both good planes, I had an EASY SPORT till the elevator servo went out and it flew to the happy hunting ground. So I went out and bought a DAZZLER and put an Evolution Engine on mine and it is a super combo, But it is a little nose heavy I can get it to hover at 1/2 Throttle. The only problem with the DAZZLER is the radio cover The nylon straps will pull apart and cause fuselage damage, so keep an eye on them if you plan to put it through a lot of negative G manuvers.

GP Dazzler & Engine selection
 

Hehe. Well, I build the elevator & stabilisor yesterday evening.

I did however modify the elevators design a bit. The original only has about 30° degrees on the diagonal side where the rudder is moving. This would not allow for a very big rudder movement. I modified this to 45° degrees, and made them a bit longer to compensate for the loss. Here a rudimentary drawing of the modification:

http://users.pandora.be/derny/pictures/modify.jpg


Black lines are the elevator as per the plans, red lines are my modification.

Crash90, it surprises me that you could not get unlimited vertical. The dazzler is a very light kit, I know of a guy who had a 3D Model that bigger & heavier than a dazzler, has a .46FX with the same prop and can torque roll it...

GP Dazzler & Engine selection
 

I had a dazzler with on OS 40SF in the nose. For those of you who are relatively new, that would be the equivalent to a 40fx. All I can say is this plane likes to be slightly tail heavy, at least if you want to get all the wild potential out of it. If you use any engine heavier than an OS 40la, be prepared to either place the servos in the rear of the plane or add 2 oz or so to the tail to get the right cg. My first flight was without any tailweight and the plane felt very heavy, especially in turns and on landing, the tail weight corrected this but it still landed hot. I"m building an uproar now and I"ll locate the servos in the back so as not to add weight excessive weight for the new OS 46fx motor I'm putting on it.

GP Dazzler & Engine selection
 

Hi Dazzler,
I also built the GP Dazzler a few years back. I had put an OS 40 LA on it with a 10X5 APC prop, with pretty good performance. It just could'nt hold a hover though, but otherwise it flew great!
The next year I wanted to try some hovering, so I replaced my 40 LA with a 46 LA, that was on my trainer. I put a 11x4 APC on the 46 LA and I was able to hover it!! And I'm still able to hover it with the 46 LA and a 11x4 APC prop!
It works fine for me and I wish you good luck with your Dazzler!
Manny, Ohio

GP Dazzler & Engine selection
 

I have put an old fox 50 on mine and I hope to be able to tell you more about it in a couple of days but on the run ups I have done at home it seems to be the best engine I have ever seen!

GP Dazzler & Engine selection
 

OK, I've also just bought a Lasermodels "3D Laser"

I just love the quality of those lasermodels kits, and while at the LHS last week I simply could not resist...

(it's this one for those unfamiliar with it:
http://www.lasermodels.com/html/m04306.html )

Anyway, I don't want to spend a fortune on engines for every plane, so I was thinking about getting an engine that would be fine for the both of them.

The Laser 3D has 10" more wingspan, is almost 19" longer, has almost a double wing area, but is less than 1 lb heavier.

Mfg recommends a .46 to .53 engine. I was thinking about the new OS .50SX here.

Now, could I use the .50SX in the Dazzler, or would that be just to much ? (It's the same weight as a 46FX, and I can always put the elevator&rudder servos in the tail to compensate right?)

Well, just curious about your opinions!

GP Dazzler & Engine selection
 

Dazzler_BE:

That Laser 3D looks like a very nice airplane. But it also looks like one I'd be far moe inclined to use a 60 engine on, although if you keep it light the 50 will do fine. Just sprightlier with the 60.

But why don't you just leave the 50 in the other plane, and when you feel you can do it, buy another engine for the Laser?

Are you planning to switch the radio gear also? A royal pain.

Bill.

GP Dazzler & Engine selection
 

I have a Futaba 6XAS, so I have memory to store a few different models.

I also put servo's in all my planes, and I have 3 Receivers that I swap around from plane to plane depending on which I will fly.

So as far as radio equipment goes: No investments there!

Just the engines though!!

.46 FX is fine
 

I currently fly a dazzler and I have an OS .46FX on it and it screams, it has good performance, besides you dont want it to go too fast its small enough to lose in the sky anyways.

GP Dazzler & Engine selection
 

Dazzler_BE:

Sorry, I remember when I had only one engine, a McCoy 19 rear intake, that I switched among my few airplanes. And at the time I thought a 19 was a big engine.

When I got my first 29 I was in "Hog Heaven."

Contrast that to last week when Santa Claus (Father Christmas to you) brought me three Pairs of engines for my new twins. Yes, six new engines. And yes, I did have to bribe him with a check. Actually plastic, but who cares.

If you keep at it you will get to the same point. But then you'll want them all to be four stroke. Never satisfied.

My current desire is not only four stroke, but multi, or at least two cylinders.

I am at the moment gathering my nerve to order a pair of radials for my latest F7F Tigercat. Price? Ouch.

Bill.

GP Dazzler & Engine selection
 

Wow, Christmas sure comes early in Florida!