Brian Taylor Mosquito

Wingnutz · February 25, 2018, 10:33:31 PM

Quote from: electroflyer on January 07, 2018, 04:14:32 PM

Techie details, The model is 71" wingspan and I am trying a couple of 600 Kv motors from Turnigy. L5055's. Looks pretty solid. I am looking at two 4 or 5s batteries running separately.

Glenn,
Applause for yet another classic build by a TEMAC original. You guys are truly an inspiration.
I'm curious about the decision to go with "two ...batteries running separately". Can you explain why two rather than one feeding both motors?
I have to decide for a model in my build queue.
Thanks,
Bill

electroflyer · February 26, 2018, 05:13:59 PM

Hi Bill,
Thanks for the kind words.
The reason for two separate systems powering this model is to ensure maximum power and performance is possible. Also I hoping to swing two three bladed props over 15" in diameter to have that scale appearance, these props probably will like to consume a lot of amps at full power.
The final reason is to ensure balance. I am counting on two 4s 5000mah batteries to help reduce the amount of lead required.

Glenn

Wingnutz · February 26, 2018, 07:56:42 PM

Quote from: electroflyer on February 26, 2018, 05:13:59 PM
The reason for two separate systems powering this model is to ensure maximum power and performance is possible. Also I hoping to swing two three bladed props over 15" in diameter to have that scale appearance, these props probably will like to consume a lot of amps at full power.
The final reason is to ensure balance. I am counting on two 4s 5000mah batteries to help reduce the amount of lead required.
Glenn

Glenn,
Thanks for answering so promptly. Your reward is another question!
I understand the CG consideration. The Mossie's nose is short and barely makes it past the props.
I do not understand why wiring each motor separately will improve performance over using both batteries in parallel to power both motors. I worry that with two separately wired motors, if one side weakens or dies, throttle response will be unbalanced leading to some cardiac moments for the pilot. Thanks for any light you can shed.
BTW, I applaud your choice to put the ESCs in the rad openings...did you eliminate the traditional leading edge here?

Michael · February 26, 2018, 08:36:53 PM

Bill, with one battery, a model can still have problems with one speed control or one motor or one propeller anyway.

My Top Flite DC3 (one battery for both motors) once lost a prop on one side in flight. I didn't notice the lost prop, but I did notice sluggish performance. I still flew the plane for 5 minutes, and had some trouble in turns to one direction, but I still flew and landed successfully. Only after landing did I notice a prop was missing.

Also, I had an E-Flite Deuces Wild model, and a Hangar 9 Twin Otter, and each of those planes had separate batteries, one in each nacelle, and never a problem, in many years of successful flying.

I suppose the risk of having a problem with two batteries may not be all that different from the risk of having one battery, where power can be lost to both motors.

Either way, the risk with electric power systems is significantly lower than with internal combustion engines.

electroflyer · February 26, 2018, 09:55:37 PM

I am sort of betting on the odd's that having two separate systems operating in the same power band will provide a stable power and thrust . I have tried using a single battery powering two motors in the past with both round cells and lipo batteries and dealt with both weak power and short flights. If the voltages are good I suspect that it will be a good perfomer....fingers crossed.

Wingnutz · February 27, 2018, 08:09:14 AM

Thanks Michael, Glenn,
I appreciate your willingness to share your expertise and experience. Seems there are pros and cons to wiring a twin separately or from one battery source but considering the points you both have made I'm leaning to wiring separately, even if both batteries end up in the nose for CG considerations.
My twin engine models are all wired from one battery in the fuse and the separate wiring choice piqued my curiosity.
The two of you are exceptional builders and pilots and regardless of how the battery(ies) is/are wired, your models have a pretty good chance of coming back in one piece.
Thanks again.
Bill

Frank v B · February 27, 2018, 03:06:57 PM

Glenn,

While looking for the plans of a Beech 18 project for Rob I came across a set of plans for a 1:18 scale Mosquito (44" span) but it has all the detailed drawings of the geometry for the retractable landing gear. It shows all the hinge points and has scale drawings of all the parts. You may get some ideas from these plans, including... staying away from them.

Robert J. Caso, published RCM&E June 2011. http://www.modelflying.co.uk/albums/member_album.asp?a=15411

I will bring to the build class tomorrow (Feb 28)

Frank

electroflyer · March 05, 2018, 08:52:33 AM

Hi Frank,

Thanks for being so considerate, I was on vacation and unable to attend the meeting. That being said, yesterday, I was diligently working away on the elevator and rudder controls. I need to get this completed as the horns will be encapsulated within a tailcone . I am not sure that I will make that removable, so care must be taken at this stage to ensure that the movements are not interfering as the tailwheel retract mechanism, rudder horn, elevator horn are all within very tight confines. I will post a photo later on today.

electroflyer · April 02, 2018, 12:41:57 PM

Hey Guys!

It has been a while since I posted, but due to extra hours at work, building has been reduced to a crawl. This weekend however, I gave the Mosquito a concentrated kick start which paid off big time.
1) Flaps are configured
2) ailerons hooked up
3) motors installed
4)esc's wired up and installed throughout the wing and located where maximum cooling can be achieved
5) landing gear mounts started.

I have also started sheeting the underside of the wing. When this is complete, the Nacelles can be started.
Here are a few photos, one shows the busy tail section which has rudder, elevator, retractable tail wheel and pull/pull steering.

Glenn

octagon · April 02, 2018, 07:18:01 PM

Fantastic work Glenn. Looking forward to seeing this one for sure!

sihinch · April 02, 2018, 07:19:37 PM

Wow! Looks amazing Glenn.

I remember reading about those style of "levers" that you used for the ailerons when I was 16 years old! It was some of my earliest introductions to mechanics. Very nice.

Andy Hoffer · April 02, 2018, 08:39:48 PM

Hey @electroflyer ,

I love your tail wheel hardware store!!! You should do the tail-cone in clear plexi!! What a show piece!!

Andy

Wingnutz · April 03, 2018, 10:32:01 AM

Glenn,
Congratulations on yet another epic build! You continue to impress and inspire.
I'm particularly fascinated with your placement of the ESCs as I pondered doing the same on my 63" Mosquito and decided against it. It would have involved cutting away the leading edge between the nacelles and fuse and compromising the D box section in that area. I chickened out and put the ESCs in the landing gear bays. I don't have gear doors so there's lots of airflow.
In your post you mention locating the ESCs to maximize cooling. I can see from you photos where the cool air will come in but it's not so easy to see where the warmed air gets out of the wing.
1. Did you strengthen the wing between nacelle and fuse to compensate for the absence of a leading edge?
2. Is there some kind of exhaust venting in the ESC "bays" or is the plan for the warm air to escape through the leading edge area?...
Once again, thanks for any time you can take to help me learn...

electroflyer · April 03, 2018, 02:33:24 PM

Hi Bill,

The Beauty of the Brian Taylor version is that he incorporated many scale details into the design. If you were to look at an actual construction photo of a Mosquito on an assembly line, you would be surprised to see the model. The two half construction, wing mount notch, frontal hatch in front of windshield and the wing radiators.
The wing radiator assemblies are reinforced with a bit thicker wood, but basically, they are just hollow spots which held radiators on the full size plane and ESC's in mine. For cooling, a scale door will be open from the bottom as with the Full size. If I can find a picture I will add later. On a side note, the cooling doors were so effective that they actually changed the attitude of the aircraft in flight.
By the way, I really enjoyed you flying your Mosquito and would love to see you bring to TEMAC this summer if you are so inclined!!

Glenn

Wingnutz · April 03, 2018, 07:31:22 PM

Quote from: electroflyer on April 03, 2018, 02:33:24 PM
Hi Bill,

The Beauty of the Brian Taylor version is that he incorporated many scale details into the design. If you were to look at an actual construction photo of a Mosquito on an assembly line, you would be surprised to see the model. The two half construction, wing mount notch, frontal hatch in front of windshield and the wing radiators.
The wing radiator assemblies are reinforced with a bit thicker wood, but basically, they are just hollow spots which held radiators on the full size plane and ESC's in mine. For cooling, a scale door will be open from the bottom as with the Full size. If I can find a picture I will add later. On a side note, the cooling doors were so effective that they actually changed the attitude of the aircraft in flight.
By the way, I really enjoyed you flying your Mosquito and would love to see you bring to TEMAC this summer if you are so inclined!!
Glenn

Thanks Glenn,
Your reply motivated me to Google a bit and I found the photo below.
I will try to get to ROGO for Mayden Fest, Jets Day, Cub Day, Warbirds Day (with the Mosquito) and BofB day...