fast_mag

I have jumped into the mosquito swarm as well after very little hesitation. I am generally more of a builder but figure I should probably try an arf first as a teething excercise. Later I might go for a Brian Taylor scratch build if I manage to get this one flying properly. I have more or less decided for thefollowing setup:
Two pumped Webra speed 40 (I run only Webras by pure principle since they went out of business) with a single large fuel tank in the central bomb compartment, dynamix carbs or perhaps Perry if I run into trouble. Probably side mounted. I will attempt 11x5 or 12x5 props. I am contemplating a Bisson or a Jtec pitts style muffler. If I go for inverted I’ll select the mufflers accordingly…
Spinners from Traplet: http://shop.traplet.com/product.aspx?c=2619; they are for the Brian Taylor 71 inch Mosquito and they are a few mm too small. I will report compliance when they are in hand if somebody is interested.
Gear mechanics from e-flite;the 60-120 gear appear sturdy enough.
Homemade struts; Will report ifsomebody is interested.
CG at 118 mm behind wing root by the fuse. Here I have read everything between 110 and 120. What’s the real deal? I suppose it matters if you take the upper or lower LE by the fuse asreference since it is not cut vertically? 118mm behind the upper LE correspondsto about 112 mm lower LE…
Something like 2 degree outwards thrust as described somewhere in the thread in order to make handling“easier” on one engine…
I figure that weight need to be saved in the tail, thus no extravaganza like tail wheel retract; every gram in the tail will require 6 in the nose to balance…
I have questions about the servo performance requirements: I can understand if the aileron servos and maybe the flaps need to be high torque, but why the elevator and rudder servos? Unlike the aileron and flaps there is very little static force applied on the elevator and rudder…? Would somebody be willing to explain?
Apparently the full scale aircraft used the wheel brakes to steer on the ground. Did anybody try ?
Does anybody have experience with the bisson or Jtec .40 size pitts muffler concerning noise or power loss? I normally try to fit a tuned silent pipe in the fuselage but here it seems rather difficult…
Cheers,
Magnus

david polley

Dear PeaterF

It is absolutely beautiful. You did a wonderful job on the model, so much so that it looks real... Try and get some more video of the model in flight. Would love to see that.... Thank you so much for sharing...

David

david polley

Waiting to hear from you....

Sincerely,

David

fast_mag

Colleagues,
I have started my building and some pics with comments are available on
http://hansenm.web.cern.ch/hansenm/p...eDirectory.htm

After working for a few minutes with the very brittle ply in the kit I decided to clean out the compartments behind the engines. I lined the sides with 1.5mm ply doubled the firewall with 6mm ply. The weight added is about 50g, all in front of the CG [img]file:///C:/Users/hansenm/AppData/Local/Temp/msohtmlclip1/01/clip_image001.gif[/img].

I opened up the stomach to add the tank. It will end up behind the CG.Here some 25 grams were added, behind the CG this time [img]file:///C:/Users/hansenm/AppData/Local/Temp/msohtmlclip1/01/clip_image001.gif[/img].

By the way: I went for the Bisson mufflers.

I'll continue after Easter.
/Magnus

david polley

Hey Smokey,

Did you ever get you Mosquito in the air... Just checking in...

David

kahloq

page 54 is all screwed up for me so i cannot see anything posted on this page. This happened once before on a different thread and once the post got to the next page(in this case 55) I should be able to see things again.

So appologies if anyone has said anything expecting a response from me as i cannot see squat on pg 54. I wont even be able to see this post either.

david polley

This is a test of the CMP Mosquito Forum

david polley

Dear fast_mag

CG should be at the 110 mm point measuered between the nacells and the fuselage on a CG machine.....with it right side up and with the gear up in the wing if you have retracts....

David

spitty

Hello to all Mosquito Fans,

at first, let me say thanks to all who have written their experience with the CMP Mosquito.

It was so important ( CG ) and helpful, and after reading the whole thread I will start building my Mossi next week.

She should be a " Trainer " before I go on with my 100 " Mick Reeves Mosquito.

I Think it´s a good Idea to have ( hopefully ) flown a twinengine model before.

And after reading TWINMANS tips:

- never start with an warbird : but she´s so nice

- never start with a taildragger : but the Mossi is one

- never install engines inverted : but it looks much nicer.

I hope everything will work fine and I don´t make a mistake..


I will try it , and that´s what makes our hobby so amazing..

My Setup :

- Saito FA-72 B / inverted, with onboard glow

- Will extend the nacalles , so no work on the firewall

- with 2 Spinners from BT 71 " , the outline will be scale enough ( Magnus, nice that You have start a buildlog )

- Mechanical Retracts from http://www.einziehfahrwerk.de/index.htm , they have build one for the CMP Mossi , around 230 $

- Colors will be the PR Blue PR XVI Reconnaissance version

- CG at 110 mm inside Fuselage

- 2 wonderful RAF Pilots from Matt : http://www.scalepilotsusa.com/1_10_RAF_Pilot.html

So I will post some pics in near Future and I wish all Mosquito Pilots many nice Flights and Happy Eastern

Andy

david polley

Dear Spitty,

Welcome aboard...WOW love those retractsThose look really nice. Hope your model does well....
Yes, this twin engine tail dragger can be difficult to take off, especialy off ofa paved runway, but if you read all of the threads you can work around those challanges and get your bird in the air too...Hope all goes well with you model...

One of the things I did to my model was add these leading edges as shown in the photos below. I have had trouble bringing the bird in on final and having those smooth landings you would love to see likd they do with the real mosquito.. I know several folks in this forum have figured all of that out with increased speeds, full flaps and such and when their flaps are engaged their radio is programmed to drop down the elevator so the model doesn't start climbing in the air.... I know some may be using a small gyro in the rudder to stabilize it on the ground..... I for one have not had those nicer things but have struggled through several models of the CMP mossy to get where I am now.....

My first 3models tended to drop and stop flying because of the ground effect and even though I do engage theflaps which helped some in the past, my model had the tendancy to drop out and stop flyingthe last 2 feet or so before I hit the ground...Coming in at faster speeds anda good strong head wind on the approachhelped too. However this model I believe hashad issues due to those flat spots on the leading edge across the widest part of the wing, taking away any available washout the wing may have had built into it. These spots had decals on the first run that simulated radiator intakes but inlater versions of the kitthose decalswere eliminated.....

I have since added these leading edges to help keep the model in the air at slower speedsand not stall on the approach. Ihave had only one flight with my newest model butit landed very smoothly in a pretty strong cross wind and I was very pleased the the model kept flying right to when the wheels touched the ground... I have hadthree other models of theCMP mosquitobefore this fourth one, and with all the setups exactly the same as with the first three, the 4th model landed the best so far... Time and more flights will only tell how much the leading edges have helped with the approaches, but I do know that I have simulated some kind of washout in the wing with these attached. Ialso know they do not hurt anything with them on there, so there they will stay.....

Good Luck

David

BlkHwkCE

Well, I ordered it... Be here Monday... Got a pair of O.S. 46's for power. Any suggestions or modifications anyone feels I need to make for a grass runway?

spitty

Dear David,

thanks for the nice welcome.

Your Idea with the leading edge is pretty good, but I wanna install a near scale leading edge, so it´s not so flat and I hope, it will have similar

effect.

But one little question : what is the size of Your Wheels?

Regards

Spitty

david polley

Dear BlkHwkCE

Throw out the fixed gear if you plan on using them. I know they look really strong, but they will bend and fold from the stress of the engines pulling the model very hard left and then you pulling it back hard right rudder and so on....again in grass this may not be as bad, especially with the O.S.46 engines. I use Top Flight11 x 6 power pointprops on mine...If you go to a 3 bladed prop read the forum and see what others have used.....If you use retracts, makesure you balance the model with the retracts in the up position in the wing...
CG isvery critical.....After trial and error with my first model that I crashed and my second model that I almost crashed the same way....the CG for this model is 110 mm measured betweenthe nacells and the fuselage on a CG balance machine and in the upright position. Theinstructions arewrong....(at least thedrawings are wrongwithwhat little instructions there are.....)

If you go with fixed gear, Fultz makes a wonderful adjustable dual strut gear that is really strong and easy to install. Photo enclosed...

DO Not take off the model with the flaps down...It will snap roll and go in... When landing I use about20 degrees of flap, just enoughto not make the model climb when engagedand yet give the model stability on the approach...And as you may have read a few posts ago, I added leading edges in thoseflat spot areas on the wing...I think it helps myself, but time will tell on that....

You are really going to have to beef up the landing gear blocks. This model uses Obeche wood from China for their "hardwoods" and the material is very soft andporous. Your second or third landing even if is gentle could rip out the gear blocks if you don't add some real hardwood on top and under the original gear block. I even used brass inserts on one of my mosquito models and that ripped out too... (I have had 4 of them now....)

Use digital servos minium for the flaps, elevator, andespecially therudder. Make sure your rudder throw is setat the absolute maxium. You will need every bit of "right rudder" (as viewed from the rear) as you can muster as you start your take off run... I suspect that taking off fromgrass will make this a littleeasier. Also, I ended up exiting out of the fuselage and going directly to the base of the rudder instead of the small wheel collar attachment that comes with the kit. Mine kept stripping out no matter how tight I made the collar and even grinding out flat spots. I know it looks "not so scale" with the push rod hanging out as you can see in this photo, but the rudder now operates swiftly and effectively. If you can't get the model off of the ground becase it looks better hidden, what's the difference.....? Your still not going to fly....

Make sure you engines are broken in really well and get them to run as close as possible in the throttle up mode. I used Dubro servo saver spring assemblies in my model and you can read all about how to install them in some of my other posts. Yes these are mechanical and not programmed but that is the beauty of doing things "old school" sometimes... I have a video link of my thirdmodel on a test flight without the nacells attachedthat is short but to the point with perfectly "mechanically" tuned engines...the link is...
www.youtube.com/watch?v=zZPewtLpsCE

Good luck with your mosquito...

David

david polley

Dear Spitty,

Since I fly off of pavement, the wheels were extremely important in keeping the model stabilized on the take off run....I used "Dave Brown" 3 and1/2 inchwheels on my model. Mostly for the purpose ofcausing "braking action" on the pavement and not have the model spin andpiroutte as a lot of tail draggers can. This was a real problem for me with this model because of the weak fixed landing gear from the kit, very poor wood block structure, weak rudder action I was experiancing using a standard sport servo, and 2 powerful engines wanting to pull the model very hard left into the grass......
Itook the wheels and first pulled them apart so I coulduse several drops of CAto gluethem back together again...waiting for about a 1/2 hour for the glue to cure since very little air could get into that area, Ithen drilled the wheels to fit the gear Iwasusing...
If you don't glue the 2 halves of the wheel thaywill pop apart and spreadout and stop turning which caused another setof problems...

My model ended up weighing about 12 and 1/2 pounds but I need the wheels to squish up so I could control the model on the ground.I could not go with Dave Brown4 inch wheels because the material they use changes to a harder type of rubber that is not as flexable as the 3 1/2 inch wheels they make....Hence Ikind of have brakes whenI taxi my model and then as Irun up the engines and pick up speed, the wheels start to back off as the model lifts into theair...What is even nicer iswhen I land my model the reverse happens as Ibring the model in on the runway.Thewheels start to squish upagain causing the model to slow down and not taxi for another20 yards, instead it slows to a crawl after about 100 feet which I really like because I don't have to fetch the model after it may have rolled and finally flipped over so something like that....

Ihave a video of me flying my model in slow motion with a nice soundtrack to go with it and you can see how the take off and landing goes with these wheels.... Enjoy the video...

The link is www.youtube.com/watch?v=7j-pCLKLqAc


David
Hope this helped

David

BlkHwkCE

David,

Thanks for the info, I have order retracts for the plane and am using digital servos on all control surfaces and analog for throttles. When it comes in I will take some pictures of the landing gear block and see if its the same as the one you received. I have heard that CMP has made some modifications to it. In any case if not you can let me know that too The plane should be in on Monday and im getting excited!

-Rob

david polley

Dear BlkHwkCE,

Ihave not seen the changes in the wood used for the gear blocks... I used2 pieces of 1/8 in hardwood that I cut tothe size of the area thatthe gear block mountsand glued them in with aheavy dose ofepoxy. I glued themon the bottom under thegear block and on top of the gear block using small wood screwsto keep them into place. Since I had the Fultz Dual Strut adjustable fixed gear, Ithen used a 1/4 inch hole saw to drill out the center of where the Fultz gear mounted and I could then adjust the height of the gear exactly where I needed it.

I mounted the fixed gear using eight1/4x2.5inch longsocket head screws that go completely through all of the glued wood plates and secured them with blind nuts at the bottom... Ithen backed out all of the screws and cut all of the screws with a bolt cutterto the proper length so they were flush with the bottom rails. This insured that the gas tanks would not have unexpected holes punchedin them when I pushed them into place....

Since you are using retracts, you can glue in hardwood rails on top and the bottom to keep the area clear for you retracts to move up and down in the notched area provided.... You can flush mount the wood screws to secure the rails until the glue sets and then you can back them out before the epoxy completely cures....

David

BlkHwkCE

Quick question, Getting all my parts ordered for my Mossie... are all the servo's standard size? [&:] I plan on having Micro servos on the throttles just to save a tiny bit of weight and maybe a high torque metal gear micro servo on the flaps but other than that just curious...

Oh and also, the product features says "seven to nine servos (rudder x1, elevator x1, FLAPS x1?, one for each aileron x2, one for each throttle x2, one for each optional retract x2) Is the 1 servo for flaps correct?

And finally- Since I have not seen the model yet does anyone think a small 10cc Gasser might fit?

kahloq

The way the flaps ar setup uses bell cranks from one servo to move both flaps.
As for throttle servos, all servos on this plane are designed for standard size. You wont save any weight using a micro servo since you'd have to add wood or something to make a smaller mounting location. Niow...I suppose you could get ingenious and find a different way to mount servos, but you''ll need to figure out where your throttle linkage needs to be on whatever motors your gonna use first.

I dont know if 10cc gassers would fly the plane. Im not familar with gas motors that small. All I know is a 14cc saito 82 gas equivalent would be fine for flying the plane....but then thats a 4 stroke also...a 2 stroke 10cc might do it. Friend of mine has two .36 size glow 2 strokes and it flies the plane ok, but its not all that fast.
As for fitting? No clue. The cowls are pretty small.

To give you an idea...the pic shows mine on the left with saito .91s and the one on the right has the .36 2 strokes.

fast_mag

Hello,

Thanks David for confirmation about the CG! I'll take a pic later. I am thinking that I might do your LE mod...

I am back again after Easter and I have updated the build log:
http://hansenm.web.cern.ch/hansenm/p...eDirectory.htm

I mounted the gears. A video is available on http://hansenm.web.cern.ch/hansenm/p.../gear_test.AVI
It can be safely played with windows media player.

I am waiting for the mufflers thus I started looking at the tail. The rudder linkage appear really on the light side and looks like it would flex more than you really want for firm rudder handling... Are you guys using it or did you modify? I saw Davids mod which might be the way for me to go too... or I might put a pull - pull to save weight in the rear...

Cheers,
/Magnus

BlkHwkCE

What spinner are you using on the 3 blade mossie?

Also what does everyone think about a single fuel tank for dual 46's or you think gravity with the long tubes would lean the engine into a stall?

fast_mag

BlkHwkCE

I am planning to use a single tank. Without having the actual experience  with two engines on one tank I believe you will have to install two pumps, one for each engine, and two clunks in the tank. This is the setup I am aiming at.

The nice things with a single tank are
- The two engines will run dry at roughly the same time regardless of individual consumption
- The tank can be mounted centrally and in the Mossy below the carbs even in inverted position!!!

I am using pumps generally when i put the tank over the CG. This is not easily achievable in the Mossy. Mine end up behind...
The drawback is complication...
Your choise!

Magnus

david polley

Dear BlkHwkCE

Dave Brown products makes a very nice 3 1/2 inch Spinner as shown her in this photo I sent you They are about half the cost of Tru-Turn spinners and look great. Dave Brown doesn't advertise 3 bladed spinners much but they will take annewspinner and cut it into a 3 bladed piece for Ibelieve$5.00 for the pair on top the2 blade spinner price.....

I can also tell you all about the gravity pull on the tanks. I know to get a good 10 minute flight I had to have 10 oz tanks. Of courst the tanks that came with the kit are not even 8 ounces because the manufacturer suggested engine sizes between a 25 and a 32 sized motor...

Start with Plan A....
By now you will have read that this bird is going to be 11 to 13 pounds and using anything less than a powerful40 sized engine will not get you off the ground...
I cut out the area where the tanks are supposed to be installed and made roomfor Sullivan 10 oz. round tanks.
My first model used O.S. 45 FSR ABC enginesthat I thought would work just fine on the model...Because they had the smaller "4BK" carburetors, they did not suck the fuel very well at all. The engines always leaned outtoo much when the tank emptied to about a 1/2 a tank of gas. When I tried to richen up the engines to make up for when they might lean out then I did not have enough power to get the model off of theground....... It was a disaster waiting ot happen....

Go to Plan B.....Itook out the O.S.45 FRS engines and replaced them with O.S. 40 SF engines that really made a difference. They were a smaller engine so to speak but had a much larger carburetor which in turn gave me more power. These engines used a "4D" carburetor and I discovered that they drew the fuel much better.
However, they were still ABC engines and required about a minute or twoof warm upfor the tank pressure to equalize and bring the engines up to speed. So...., I was back to a7 minute flight because I had to waste time and fuel waiting for the engines to come up togetherto havethe power to get the model off of the ground. You have to have powerto get the model off of the ground. You need power and lots of it......Also I could not use 11inch props on the O.S. 40's because they would justload up and overheat ifI was not very carefulabout the needle valve settings. Not haveing 11 inch props really hurts the performance of the model on the groundbecause there is no propwash on the rudder at allwith the 10 x 5 props Iended up using to maintain power of the engines in flight. Truth be told, 12 inch props would do the job with propwashhitting the tail section and help more with controlof the model on the ground. I always ended up takingoff the model with pure engine speed and no assistance on the propwash. The rudder has no effect on the model until youget enough airspeed to have it have any effect on theground, especially on pavement, hence you need lot's of power to get the airspeed quickly for rudder effectiveness...

I have a video link of our 50th anniversary air show that was shotbefore the start of the show on Saturday morning...Torwards the end of the video they shot me warming up my mosquito for the days activities. As youcan see it took time for the enginestosyncup and have themodel ready for my first event. You can also see the 10 inch props during the warm up and they just don't look very scale like, but they did the job with the engines I had at the time.......That link ishttp://www.youtube.com/watch?v=KPuDOZsQOQY

Go to Plan C....I replaced the O.S. 40 SF engines (I rebuild engines all of the time...It is one of the things I really enjoyabout the hobby) with "Ringed" 40 SF engines I rebuilt purchasing off of the internet.

After breaking them in, which ringed engines need a lot of, they workd out better as far as not having to wait for the engines to heat up and come up to speed...I got an extra minute or so with the ringed 40's but still had to keep using the 10 inch prop. I was still struggling to get the model off of the runway...If there was a crosswind on the paved runway, it was almost impossible to get the model off of the ground.....

Sooo......go to Plan D of which I purchase my 4th kit and ended up using my second fuselage since it was all still intact from the mishap I had with my 3rd model....NowI went for the O.S46 FX engine which allows me to use 11 x6 inch props which look closer to scale, and I have a lot of power to get the model off of the gound. Ihave no draw problemat allwith the 10 oz tanksgas tanks. The only problem I had with the 46 FX engines is there was barely enough space to mount them and still use the cowls...Because the needle valveis in the rear of the 46 FX, Ihad no room to mount the engineand have enough space back there to work out all of the plumbing for the gas lines and use a quick fill mount to fill the gas tanks with.
I ended up replacing the "40D"carburertor and remote needle valve on the 46 FX with the older 40 SF "4D"carburetors that have the needle valve near the front of the engine. Iused the rear engine covers off the 40 SF enginesas well... The 46 FXengines run great with the older "4D"needle valves up front...Now I had the room to bring through the fuel lines and the quick fill mounts as well..(...Photobelow...)

Ibelive you really need to use seperate gas tanks...The engines have to run together as closely as you can get them from idle and transistioning to full rpm...If one engine is off in the transistion the model is going to pull even worse to one side and you will not have success. When the engines are perfect..., it is still going to pull very hard to the left, but with power you can recover very quickly because the rudder will be much more valuble in keeping the model going straight....

David

BlkHwkCE

Mossie came in on Monday and I already have the engines mounted tanks installed and servo's.... Which brings me to a question, In the manual if you want to call it that. It shows the throttle linkage coming past the carb and turning back toward the motor? I see the concept but do not understand the reasoning. If anyone has some pictures of the throttle linkages under the cowl that would be highly appreciated. I am running O.S. 46's FYI

Thanks in advance!

BlkHwkCE

So due to my ADD I just couldn't wait to mount the engines... I got them all mounted up (still no throttle linkage) and ran hand linkages to the carbs... Anyhow the sound of those two beautiful O.S.'s humming is some sort of euphoria, If it were not for this dumb work thing and business trip this week it would be flying this coming weekend

david polley

Dear BlkHwkCE,

I used Sullivan golden flexrods for the throttle linkages on both engines. (see photo) They are really easy to install, basiclly drilling a hole next to the motor mount and then padding with small pieces of hardwood along the fixed plastic tube with epoxy, right up to the servo arm.
This will make the guide tube very stiff and yet allow the flexibility of the golden rod to curl through the firewall to meet the servo arm.

I then crimped and then soldered the threaded brass fitting on the the flex cable and then used aplastic clevise (photo enclosed)to secure to the throttle arm of the engine. The brass clevises that come with the throttle cables are nice but they will have a little slop in themwhen moved and you do not want any kind offlex or extra movementon these setups so that both engines run together from idle to full power and everything in between.

When you get ready to cut flexible cable you will have to use a dremel tool and cut off wheel to cut it clean. Even large wire cutters will make the end of theflex cable unravel, so the dremel tool does a great job of cutting thecable cleanly....

Since you are using 46FX engines, I will tell you what I did to keep the engines running as close together as possible through the transistion of idle to full throttle... You are fortunate in that you have carburetors that have the throttle stop set screws on you engines. (see photo)You can set those screws so the engines will not actually shut off just by tweeking them down until the carburetor opening is just barely visible. Thespringsunder the set screws on the carburetors are very stiff and once set those adjustments will not move....

Of course you will have to fine tune them once they are installed, but my point is that I use these dubro servo guard spring assemblies (photo enclosed)and hook them up to the servo...In the instructions you will have a feed through brass post that you push down and secure on your servo arm, then you place a spring on each side of the post through the throttle flex cable butting the spring upto the feed throughpost andthenadding the screw down stops on the other side of the of the spring. Once you align everyting, you then tighten down those screws on the flex cable and now the springs will collopse when at full throttle and in the idle position while still protecting the servo and allowing full transiston of your servo as if it was just a solid piece of wire.They are really slick....

With this set up the spring will complete the transition of the servo so it does not bind and chatter while still securing your throttle arm to the throttle stop position you have set you carburetor screw.Now you can set your engine fora really nice idle speed and match the other engine atthe same time...They come with 2 different sets of springs of which one set is stiffer than the other so you candecide what works best for your installiation....

Because the spring is still taught when you throttle down, you can adjust your throttle stop screw in and out for the perfect idle of each engine without the servo drawing current it would normally if it was buzzing with the adjustments you have made.. I realize that you will not be able to shut off the engines with your transmitter with this set up, but since the idle speed is so low you can just cup your hand around your spinner to stop the engines..... You have to have these engines running together as close as possible and I have found that is such a comfort knowing that when I bring my throttle stick down to land that I do not have to fool around with the throttle trim, trying to find that perfect spot where you can land or mayby have to go around again or worse that one of the engines quit because the carb closed on one engine while the other was still running.

I could take my model apart and take photos of my setupbutI wastrying to avoid having to take all of those screws out from the nacells and thewheel wellcovers....If need be I will do that for you ifit will helpand you can see what I have if you wish....

Let me know.........

David