jdp, lower pitch = thrust, higher pitch = speed. I am using a Zinger Pro 14x5 on my GMS .76 and it will hover with it.

OK, agreed, many engines do well on a 14X5 Zinger. It's allot cheaper of a prop, too.
The APC 13X4 W is a $7-8.00 prop. The same APC prop in a 14X4 W costs double that, about $14.00 or so.
I have had many, many MDS engines and typically they like the smaller diam. props, model for model. I have no experience with GMS, so I won't comment on them.
I do know that MDS engines have carb issues that tend to sag at the midrange transition, this is why I recommend the APC 13X4W.
The MDS will clearly have the needed HP to hover the Razzle, that is not in question, to me.
The question is how to best run the 78 on your plane and I stand firm on the 13X4 W.
If it doesn't work well I'll buy it back from you.
The Zinger is a wood prop, and therefore lighter than APC inch for inch. This will help the MDS spool up quicker, too.
The main thing about the APC is the prop is designed for "fun fly" type planes by having a much wider blade than the Zinger, there by getting more "bite" .

Nice thing is the Zinger is affordable, so you might as well have one or two anyway since they are wood and are prone to cracking easily.
Good luck and please keep us informed on your progress.

Well, my LHS did not have the 13x4W. I went ahead and bought a 13x8, had my hobby shop order a 13x4 and it should be in by Wed. I am going to try out the 13x8, it is not the Wide, but I will see what it can do. If it works or not I am going to throw the 13x4 on, see if it gives me more performance. Thanks for the info, I will be taking my digital camera down so I can hopefully post some photos later tommorow.

Well, I have a good feeling you won't like the 13X8 at all, it will fly the Razzel way too fast, and will have trouble slowing it down.
You may want to reconsider drilling out the prop and just use what you have untill the 13X4 gets there.
The thing about a smaller pitch is, it allows the enging to spool up quicker, thereby avoiding the hiccup at the midrange....the higher pitch 8 prop will bog the engine down in the mid range and when it does get up to full RPM will fly the plane faster than you'll want it, or it (the plane) needs to be flown.

Props are cheap enough to experiment with...Pretty much untill you get into the larger APC's....... try making notes of how each prop preforms on a given plane/engine combo.

ok, thanks.

Flew my razzle again today. Just doing some basic rolls and snaps. Had my right h.stab snap on me and the vert.stap snap off as well. Amazingly I got it back to the ground with no damage. In fact it was a great landing, just a little ways from the runway. I will post picks tonight. A lot of people have told me some good ways to reinforce it at the field. I am going to drill a hole in the vert stab, slide a 5-56 rod in and throw a lot of 30 min epoxy on her. Going to put some ply triangle blocks on the hor.stab and iron some carbon strips on the leading and trailing edges. Hope this works, will post pics when I am done.

I am guessing that the tail feathers broke due to the speed you picked up with the 13-8 prop. This plane is designed to fly low and slow aerobatics. As for the damage, I would just rebuild a new set of tailfeathers and use Basswood for the LE and TE. Just my 2¢

Yes, that may have been it,but I was flying with the engine rich and at about 1/3 and 1/2 throttle the whole flight. I think seagull models used way to soft balsa around the whole plane. They built the stabs very weak in my opinion, Even with the lower pitch prop, without reinforcement this would have happened to me in the future anyway I suppose. How do you post pics?

Mike Bogh had said he reinforced the horz fin on his with CF....I strip'd the covering off the bottom of my horz fin and sheeted it with 1/16 balsa. This made me have to cut the slot in the fuse where the horz fin rest by 1/16". I only trimed it the width of the horz fin, so that the vert fin peice would rest the rest of the way in the slot nice and tight.....So far no problems, but the wood does seem soft on my vert fin too...I run an Irvine 72 with a 13x6 prop....Gator

I maidened mine last weekend, loved it, no problems. however, after reading the posts about the weak horizontal stab I decided to streathen it--but I used heavy fishing line leader as guide wires--didn't have to go throught the verticle stab- used an eye bolt right in front of the verticle stab on fuslage-connected it with with metal control horn connectors I fashioned so I could adjust tension, and mounted underneath the fuselage. Works great and it only took 45 minutes.
Dhammer

damage...

...

..,

Send those pictures to Sean in product support at Horizon hobby and he will get you a new fuse, and tail group.

Both of the stabs that I broke were in the exact same place as yours.
Bummer, great flyer though...

Just got my servos from servo city and they sent the wrong ones.
Ordered the new 475HB's and a 625MG for the rudder. They sent me 425BB's and a 625MG. Do you guys think these would be alright with a 6 volt battery?

BTW, I'm putting a saito 100 on it, but will be flying it slow of course.

Thanks,

Alan

I think they'll be fine as long as you use 440 rods.....

It will work fine. I have a 6V 1650mah NiMh battery and have all HS-422 except throttle HS-300 and rudder HS-605BB

If you call Servo City they will make the order right. I have had very good service from them. Did you get a discount? The 475 is $3 more than the 425. Unless they got the order wrong from the start, they usually upgrade the the next best servo, etc if a part is backordered, etc.

Thanks for the quick info guys. Don't you just love RCUniverse?!!
I'm about to call them. I'll just keep these and get them to refund the difference. I've ordered from them before and this is the first
problem so i'm not too bothered by it.

Yes, i'm going with 4-40's. I've been re-covering the razzle (it was sent as a replacement for a defective ultra-stick 40) and so i did some reinforcement cross-bracing on the stab too... Hope it holds up.


Thanks again,

Alan

Hi fellow Razzle Pilots

I just finished reading the posts on the razzle. I have had mine since Jan and have flown it 5 times, each flight had structural problems. At no time did I over throttle it. The wood is so soft that you can flatten with your fingers. Slow flight aerobatics are fun. Neat plane. But I am afraid it is made from balsa affected by Agent orange. A little Viet Namese revenge? Could Be!!!

Reinforced my tail area. I put in 1/4x1/4 bass cross bracing.4-40 flying wires. There is much more strength in the horizontal stab now. Doesnt flex anymore. I am going to monokote the stab red.

...

Nice job, that ought to do it.

Thanks, my props came in the other day. Told my hobby shop to get what they could. They said there are no 13x4 apc props, I told em to get the closest thing, and what they ordered are some 13x5 wood zinger props. Mike, you know where I can get a 13x4 cf prop, or composite? thanks, Justin.

Just got done covering the horiz.stab. Doesnt look as good colored red. I am going to add some yellow, and some yellow on the bottom of the wing for some contrast from top and bottom. I am quiet pleased with my setup on the tail, very strong. No flex in either stabs. Hope it performs good tommorow. I am really going to put it to the test, maybe a few waterfalls, flat spins, ect. Let yall know it performs.