Eric.Henderson

I was wondering what size props you are using and on what engines. I use three blade and even four blade props in many different applicatons.

The size of the spinner is proving to be more of a problem. Dubro only go up to 3" on the three blade versions. (I have some 3-1/2 Tru turns but they are mainly for my pattern planes.)


BTW I am using B&D retracts with BVM hardened legs. they work well on my bigger planes so should be OK on the Mossie.

Regards,

Eric.

DragonLines

My Feedback: (13)

I'm useing Magnum .52 four strokes on this plane with 12x6 three bladed props, they turn about 9000 rpm. I have Tru Turn spinners on the plane. Not real fond of plastic spinners. I have some of the BVM legs too but it seems a little wiggly on the ground. Could be the Robart main units.

Baldeagle

My Feedback: (7)

Dragonlines How does your Mossi fly with the Magnum 52 FS? Thanks Rich

DragonLines

My Feedback: (13)

Flies fine. Plenty of power. Love the sound of the four strokes. I am having some balance problems with this one though. It shows nose heavy when I check it but fly's like it is tail heavy. Anybody had this problem?

Eric.Henderson

I had already installed the OS 52's before I read the post on the carbs coming out too low. I have moved them to side mounts now, I will also move engine back because the spinners are too far forward.

Anyone know where I can get two new cowls?

Regards,

Eric.

William Robison

My Feedback: (3)

Eric:

The Du-Bro spinners have a lip on the back plate that extends about 1/8" behind the plane of the prop driver. You might check into using them.

Bill.

Doc53

I checked the Du-Bro website and my Tower catalog but can't find a spinner larger than 3" manufactured by Du-Bro. Where are you finding a 3-1/2" one with the 1/8" backplate lip?

William Robison

My Feedback: (3)

Doc and Eric:

Oops. Thought you were using spinners smaller than you are. 3" is the biggest from Du-Bro.

Sorry.

Bill.

Hot Rod Todd

My Feedback: (1)

I have my Mosquito to the point where I'm ready to balance it. Even with the 46AX's I'll have to add weight, in addition to the 6V 2000mah battery in the nose to get the 4.5" at the wing attach CG. If I go by Spitmad's setting in an earlier post (85mm at the wing root) I'd have to add a ton of weight. I don't see how that could be correct. I may go ahead and do the calculation for the wing so I can determine what the real CG should be. Sounds like some of you have been flying it with success at the 4.5" point, so that is what I'll most likely shoot for.

Eric.Henderson

I went with CB associates spinners and then Tru-turn if I need more nose weight.

Eric.

William Robison

My Feedback: (3)

Eric:

Don't know about the larger ones, but the Du-Bro 2 1/2" plastic spinner is heavier than the Tru-Turn standard spinner of the same size.

Bill.

Doc53

Eric,
I'm planning to install FS-40's in mine, also inverted. Before you scrap those cowls and turn 'em sideways, see what your manual says on those 52's. Mine says the top of the tank should be 3/8" above the carb, and from my preliminary measuring the inverted engine should be about right. Just to be sure, I plan to mount one of my engines on the test stand and elevate the tank well above the actual height in the Mossie to see what happens. I also won't pressurize the tank from the mufflers on mine, as I've done in the past with other planes. Maybe the non-pressurized setup is why I haven't had a flooding problem?

lozza1965

chaps i'm running mine with 2 OS 52FS inverted the carb being below the tank centre line is not a problem, and by running them horizontally it means the head is going to stick out a long way looks much better inverted. also mine are mounted right back with the carb almost touching the firewall, then i built up the cowl

lozza

Doc53

Lozza,
That's good news. I've not had a problem with inverting a 4-stroke in the past, given that the engine had tight compression and no other problems. However, I've not always connected the tank vent to the muffler (or even USED a muffler, for that matter) when I made the conscious decision NOT to invert the aircraft, as is the case with the Mossie. I simply don't expect to pull a -g with it, or sustain inverted flight. +g loops and barrel rolls are still o.k. even with the tank vent open to atmosphere and not connected to a muffler, as long as the maneuver is kept at a +g level.
While on the topic, it's suprising to discover how many folks believe that their fuel tank must be "pressurized" for their engine to run. Connecting the tank vent to the muffler simply means the a/c won't vent fuel when inverted for sustained periods or when subjected to -g loads. If the engine, 2c or 4c, required positive pressure on the fuel system to run it would never start in the first place as the "pressure" is only generated with a running engine. We never HAD mufflers in the early '60's to tap for "pressure".
I just got a reply from Flair in the U.K., and they say the H.D. retracts for the Mossie are available. I'm thinking of ordering a pair. What do you think of these?

Thanks!
Gary

lozza1965

Doc
just in the process of building mossie No2 wrote off first one on take off on maiden flight (after twenty years flying i made a major silly mistake) so as always made a few mods along the way to this one, decided to do away with the silencers and like you say it will not be a problem and boy don't they sound good, i've also made air intake trumpets on the carb inlets only about 20mm long but this is to stop all the mess that these engines spit back out of the carb.

As for retracts the mechanical ones work fine, my mate DH71 this forum has then though he did make ali centre blocks the plastic ones failed on landing, myself i'm using air retracts, shame we did'nt speak a few weeks ago had a spare set of mechanicals here sold them now,

if you scoll back a few pages on here you can see pictures of our mossies and my new one is vitually identical, also check out the spinners, dh made then

lozza

DragonLines

My Feedback: (13)

Hot Rod Todd,
Let me know where you balance and how it flies. I was thinking about going to 25% of the wing cord and see where that comes out. Just not real pleased with the factory setting. I am away from home so it will be a little while before I can check this out.

spitmad

HOT ROD

the CG I calulated was 85mm from the outer wing root i.e measured on the outside of the nacelle (not between the naceele and the fuselage)
The instruction manual indicates a CG measured from the outside of the nacelle but the measurement given refers to the inside of the nacelle (from memory 125mm).
You can see from the wing that the leading edge is futher forward on the inside wing section between the fuse and nacelle.


I discovered the problem on my first flight test when the model took off and prop hung ! , i only just got it back in one piece, I then called a model magazine that did a flight test on the Mossie and the guys there told me they ignored the CG in the manual and ended up with a Kilo of balast in the nose (this included the 5 cell 1500ma battery)

Mine now flies well (like a rocket with the AXs) and lands at a managable rate with full flap.


cheers

Alan

Hot Rod Todd

My Feedback: (1)

Thanks for the advice on the CG guys. It pains me to add two pounds of weight to the nose of a plane, but that would be better than picking up the pieces. Check out the photo of my Cockpit, since it's in front of the CG I figured I might as well add some weight to it with a bit of detail.

Spitmad: what props did you end up using with the 46AX's? I was thinking of starting with 11X6's, and adjusting from there.

DragonLines

My Feedback: (13)

So Spitmad,
Did you balance at the factory recommend distance from the outside of the nacalle at the 85mm? My Mosquito did actally the same thing, hung on the prop's. Luckily the .52 four strokes had enough power to pull it straight up or it would have been lost. I only have about 3/4 oz of lead in the nose, 4.8 1200 battery. It checks nose heavy at the factory setting but we all know now thats wrong. Any comments on the control throws?

spitmad

I use 11 x 7s on the 46AX's and tune to around 11500 rpm, they will pull to 13000 but a liittle to lean on the ground so I back the revs off for insurance.

Control throws for all sufaces were as per instructions apart from flaps, I crank in as much flap as possible, this cauaes the model to balloon so I usally slow to half throttle and as the lead sled starts to loose height click in half flap , slow some more and on final approach click in the remaining. I think I have about 2 1/2" of travel on full flap which really throws out an anchor .

The other thing to watch is to ensure you have full elevator travel to allow you to flair on landing, fly it right in, with full flap you can keep the power up without gaining too much airspeed, I find three pointers are easier on the L. gear when you've got 15 lbs falling out of the sky,

I have just received a spare wing for the original Mossie I put in so I'll build a night fighter version, solid nose with guns , matt black.......something different

I'm almost ready to retire the current Mossie in favour of the B25 and P38, they are much nicer to fly and a damn sight easir to take off......another thing , with the torque steer inherent with the Mossie, takeoffs can easily end up pointing 90 degrees left of the direction you started at. The only way I can safely get the Mossie airborne is to have some hold the model, give it full noise, full right rudder and release...........not pretty but effective.

Also .....I was able to fly on one engine (when I had the OS 46 LA's fitted) but only just so if you loose an engine, kill the good one imediately and head for the strip!

have fun

DragonLines

My Feedback: (13)

I didn't have much trouble on take off roll. I'm used to taildragger twins. My four strokes match up pretty good too which helps with the torque pull. What about the distance out from the engines you balanced at? I was curious about your throws to rule out that as a problem in the planes handling. I was almost completely sure it was in the balance but it never hurts to ask. Other than being a good bit thitchy because of the balance problem I thought it flew well. i mean once I got it under control after the tail pointed down.

Alistair

Hi
I'm just building my Flair mossie with 2 asp 52's (2 stroke) and 12x6 props

I'll let this forum know how I got on !

Eric.Henderson

The center line of the carb came out at the bottom of the tank. So I rotated them 90' and recessed the engine as per the above advice. It now has a nice 1/16" gap behind the spinners. Not sure where to order new cowls, but will use what I have already.

Programmed the throttles to react to (help) the rudder duirng taxi, Put it on a switch so as to not bugger up the inflight operation with one engine out :-)

E.

Hot Rod Todd

My Feedback: (1)

I never even thought of programming the throttles to follow the rudder, but I would think with the right mix it would work great. I have my throttles plugged into seperate channels, so I'm sure I could easily do it. Let me know how it works out.

William Robison

My Feedback: (3)

Todd:

Check Twinman's posts about throttle mixing to the rudders. He's a great fan of doing this.

Bill.