VQ Models Maiden Flight Ready!

I installed the new prop on the VQM P-51B, and ran a quick test, she stayed together. Today I ran her a bit longer and did some static thrust testing.

She is about 8 lbs AUW, and using the 14" 4-blade prop with a 6S she is producing 1200W at 52A with 12 lbs of static thrust at full throttle.

This is a nice plane, but there are a couple of things that bug me. One is that the coat is rubbery, and low temp, so in the warm air it sags. I suspect this will really suck out in the sun. The second is that to change the battery the wings have to come off. 

Those two holes are where the wing bolts go. The tend to miss the hole inside and flop about the pseudo-air ram. It takes a lot of time to fish them out and try again, a process that takes several tries.

The battery compartment. Fits the 6S 4500 mAh battery fine.

I stuck rubber washers on the ends of the screws so all I need is a screwdriver and they should otherwise stay put between changes. All she needs now is for me to try and fly her.

We flew rockets today, and I caught some video from my Alpha Sport 450 and a keychain camera. An hour of that and I am pretty much done for the day.

MotionRC Delivers, Sweet Results!

I have recently started buying parts from MotionRC, and one of the things I appreciate most about a vendor is quick processing and shipping. These folks rock: part arrive 3-4 days after I order them.

I had ordered the 4-blade prop from the FMS 1700mm P-51, and it really was too big for the VQ Models P-51, coming in at 17'. I ordered the prop for the FMS 1400mm P-51, and its a very nice fit at 14". A quick test last night and she ran fine on 6S drawing about 55A and making about 1200W, but I didn't run her up completely to full throttle. This prop, like its bigger brother, has a hex shaped box on the bottom of the spinner to drive the spinner from a similarly shaped hex on the shaft of the motor. My smaller shaft (okay, I hear that...) doesn't have the hex, but it seems to work fine. It was challenging to get the prop nut secure without stripping the shaft trying to hold it while tightening it. It also took me about an hour to get the engine aligned with the cowl... for some reason it was just not staying where I put it, but once I found the sweet spot she spaced perfectly.

She is pretty much done and is ready to maiden! Does that not look awesome? I am glad MotionRC stocks these parts.

Holy shit... that scares the bejeezus out of me!

I made some major steps forward today on the VQ Models P-51B.

I installed the Corona DS329HV mini-servo's I got from Hobby King. I'd like to pretend I did it on purpose, but they were in the standard servo section and I didn't look at the measurements... But I was going on specs for torque at 6V and these met my requirements at the price I was looking to invest. It just meant I would have to modify the servo trays.

It took me a while to fish the line through the wing to pull the servo lead through. This is the original size of the opening.

I cut some plywood and fitted it to the opening and the mini-servo.

And cut a piece to fit at the top to balance the edges. It was easier to do this in two pieces.

Servo fit tested. Snug.

And installed completed. They are fast and will work well with the Orange Rx3 stabilization receiver.

Now the terrifying part...

This is the 17" 4 blade of unknown pitch from the FMS 1700mm P-51 Ferocious Frankie.

Its ginormous...

The spinner is a tad big for the cowl, but not distracting wrong.

She's gorgeous!

And when I put the Watt Meter on with a fresh new 6S, and went to just above idle to check the edges of the blades to make sure they were aligned, she made a powerful roar...

Then I slipped the throttle up to 50% and the roar became a banshee.

I got to about 65% when the Watt Meter read 1800 Watts, and she was pulling like a monster chained, and the sound was the most frightening power sound I have ever heard! This was magnificent! But if I use this prop I am going to have to put a throttle curve in and governor the max throttle down a lot! This was amazing. 

When I received the 17" prop I didn't know quite how big it was. I was trying to find a prop that fit a 60" or so plane and the 1700mm came close at 66", and the 1400mm a little short at 55".   I went with the bigger one. I think its too big, though I was planning on a 17" twin blade, with a 4-blade I need to come down a couple of inches.  I have already ordered the same prop but for the 1400mm P-51. I have no idea how big that one will be, but I expect a couple of inches shorter and better suited. I think that cone will fit well too. MotionRC is wicked fast at sending stuff, so it will be here soon. 

Damn that was scary.  I wonder if this prop, with each blade screwed to the spinner plate, could be flown on a 10cc gasser?

Tomorrow I will put the servos in for the rudder and elevator. and the plane will be essentially ready to program and fly. I am thinking of using the two Hitec HS-485HB Carbonite gear servos on those surfaces. They are analog, but I can mix analog and digital servos with the RX3 Receiver. I am still considering just using the mini-servos, but not if I am going to be drawing that kinda wattage at anytime during the flight. The ailerons can handle it, but the tail feathers will need some oomph. I also want to install the 6V 5A voltage regulator tomorrow.

I was cleaning the underside of the wing when I realized the painted on graphics were smearing. Damn. 

It would be great if the new prop arrived tomorrow, but I think another day before it does.

Huh... that was curious.

So this happened the other day...

One moment we are flying our second tank of gas in a brisk wind, the next minute we weren't. The wind was to my back and I had idled the 30cc MXS-R so couldn't hear the engine at idle. I noticed that it had quit too late, when I realized I was looking at the prop. Too low, in a turn into the wind. Ran out of altitude because I was flying at Mt Hudson and had to flare as she disappeared from view as she was going down the uphill at the end of the runway. Recall this runway is on the top of a landfill dome, so slopes hard at both ends, especially the 36 runway with an approach from the south, a steep 45 or more degree drop off.

I found her in the deep grass having only ripped off her landing gear.

I'll get those fixed in the next week or two. It'll take a major rebuild of the undercarriage. Then I will try to figure out why she suddenly quit.

To windy to maiden the Spitfire again, but I had problems with her tuning again when I decided to run her. I also noticed fuel and air bubbles coming from the gasket between the cylinder and the carb, so will need to take that apart and re-tighten it.

Flew the 10CC Sukhoi fine. She didn't like the wind on landing, and her rudder tiller broke off making her tail wheel castor.  I only flew her about 3 times before I decided that was enough for the day.

Its disappointing. There is always a brisk wind at Mt Hudson, but down below it was 1-2 mph. And I wish the runway was a little longer without the drop off.

VQM P-51 Rebuild Update

I've been making some solid headway on the rebuild of the VQM P-51 as an electric.

I removed the damaged cote repair and put invasion stripes on it, just on the right wing. They came out beautifully!

To increase the airflow, along with the aft vent, I opened up the smile under the spinner.

The installed fixed landing gear. I have servoless retracts that fit this plane, so I wanted to install them in place of the fixed gear.

Oddly, the mount space is not aligned with the strut space.

So I modified the mount space to allow the slight angle.

I then painted the insets.

Cleaned up nicely!

The retracts installed.

I made covers for the machinery ends.

Coted them and installed them using RTL Fastener servo screws.

Close up.

Sweet, deeply flush fit. This is a front on view with the gear retracted.

Gear extended.

I put a twin blade on, starting with a 14 x 8 and then a 17 x8, used a 5S and a 6S battery, and checked watts. I was stunned that the 14 drew only about 250W!  The 17 drew almost 700W. I expected more. It was impossible to find a 4 blade scale prop... I then went looking for a "replacement" for a similar sized foamie, and came across the FMS 1700mm P-51 on Motion RC. Initially they had the blade sets, but no spinners, but those came in! I ordered two sets of blades and one spinner.  I am excited to have a nice 17" four blade on this plane, making it really real like!  The 5065 motor shaft isn't tapped in the center to accept the spinner screw, so I had to locate and order one. Motion RC was NIS, but Horizon Hobby had them. They are on their way. Hope it fits my motor.

Still waiting for my Hobby King order...  I ordered the servos from Hobby King about 8 days ago, and yesterday they just left the warehouse. Hobby King's USA warehouses have been SOOOOO FUCKING SLOW getting stuff shipped that I struggle to order things from them. I have gotten stuff from their Hong Kong warehouse in the time it takes to get stuff from the US. I am really disappointed. HK Hong Kong is good, if not overly so, about sending emails updating you on the status of your order right up to your door. The US warehouses email acknowledgement of your order, but then nothing. I had contacted HK twice about the status of my order before it suddenly showed up as shipped.

All that is left is getting the servo's and installing them. I am hemming-and-hawing on using the BEC on the ESC or tapping in one. I ordered a 6V 5A one, and will likely tap it in and use it for power to the electronics. I am using the 3-Axis Receiver that will probably like having plenty of juice.

Speaking of juice... I found a great deal on 6S 4500 mAh batteries for about $42 a piece, and picked up 4 of them on eBay. Psych!

When the guy from Hobby King arrives on his bike from Oregon with my servos, I'll post another update.

VQ Models P-51B - A Used Airframe Rebuild

Amaadur Rahman, a fellow RC Pilot from SNHFE in Merrimack called me a few weeks ago and told me he had been given a VQ Models P-51B Mustang airframe that was in good condition (the wings actually measure 61 inches). It was too big for him to transport, and he thought I would enjoy repairing and setting her up, so he gave it to me! Thanks, Amaadur!

It is in pretty good condition. I am going over it carefully and am trying to keep my costs down. I have on hand a Hobbywing 100A ESC, and a HeadsUpRC 5065-04 1400 watt motor (at VQ Models estimated 7 lbs AUW, thats 200W per pound. My other choice was a 700W motor, and ain't nobody got time for 100W per lb. But that max watts is likely on a 8S battery, and I am flying it 5S, so it will be interesting to see how many watts it ends up drawing). I also have an Orange RX 3 axis stabilized receiver, brand new.

I want all metal gear, digital servos, so today I ordered 4 Corona DS329HV Digital Metal Gear Servos, and a Turnigy 5A 6V SBEC. I have 4 5S 4500 mAh batteries that may need replacing, and one 6S that likely does need replacing, and they fit. Someday I will, but once I know what she likes. I am also replacing those ugly fixed gear for retractables. I have the same servoless retracts I used on the Spitfire, and today ordered a set of struts that are for the Spitfire as this about the same size, from Tower Hobbies. They are updated from the ones that came on my Spitfire and are rather cool looking.

Today I started on the fixin' up.

The model is in pretty good shape. I can't match the stock cote, so I decided that I will put D-Day stripes on that right wing.

Its a sign that the pilot came loose, and I had to re-install him. The canopy came off easily and he's now sitting proud.

I wanted a bigger tail wheel, so I swapped it out.

The cover was on wrong and wasn't flush, so I fixed that. The tail wheel was loose on the turn thingy, so I changed out the set screw for a screw-screw and snugged it up as best I could. Leaving the weights on for now.

I rebuilt the cover and the doors and coted it. Snazzy.

Curiously there is no vent. Electric aircraft, especially one with a huge motor and ESC need a lot of airflow and most have an aft vent to allow flow-thru of cooling air. So I decided I would cut a vent hole and use a vent cover from an Eflite Pulse 25XT that I painted. Marked out the opening.

Opening made. There is nice continuous airflow, but I will make an opening in the cowl under the prop.

Epoxied for strong hold.

Vented.

The wing-fuselage cover is broken and I wasn't sure how to fix it...

I decided to use foam and wood filler.

Trimmed a piece of painters tape to mark the curve.

This is the dense wood filler I am using. I don't want to fill the entire space with it, so trimmed some foam...

And stuck it in the hole.

Then filled it with wood filler. A few hours later I light sanded it, and this weekend I will finish it. I am hoping the silver paint I have is a fair match. Its a warbird, it doesn't have to match. Not sure if it won't fall off as it won't flex well.

I installed the motor. Pretty much fit the stock holes.

I epoxied the battery tray (behind the clamps) as it was loose, and made a small cross piece to mount the receiver, here being epoxied under the clamps.

That's pretty much it for today. This weekend I will finish off that wing cover and make the vent opening in the cowl then install it. I will start repairs on the wing cote and put those invasion stripes on the top, and install the retracts, and when the struts come in those too. Same with the servos, the SBEC, and the receiver. They should all be here in the next couple of weeks! I think she is going to be a great flier.