Yeah... it's what I do.

Vortex Generators

The wings on the MX-Bach are Sbach 342 wings. The inside wing tends to tip stall on approaches if one is at all slow coming in and turns sharp to final; straight in not so much a problem. A couple of runways I land on require a tight turn to final, so this happens a lot with this plane.

I was aware of vortex generators and how they curiously maintain laminar flow below stall, and I know that some RC aircraft have them, but I didn't know if they actually worked. A while back someone on the Southern NH Flying Eagles FB page posted a video on full scale use of VGs and a post on how someone had done them on larger scale RC aircraft using styrene L angles. There is a nice run of posts on RC Forums, including this one. Then I found this and I figured, why not see what happens!

L Angle Styrene, forget where I got it, not one of my usual RC sources.

Placed them along the 1st third of the curved chord, and decided 1.5 inch from the outer edge. I placed each pair 3/4 of an inch from one another, and 1 inch between pairs. Entirely arbitrarily placed, other than the 1/3 of the curved chord, which was the recommendation in the posts.

Each one of these is a VG, I just liked the way they look in pairs, and wanted to concentrate on the tips. I used Beacon 3-in-1 craft glue for the adhesive. Simple, strong, easy to place.

Someday soon I will see what happens with them in place!

Great flying and amazing luck...

I got out to Warner Field in Hudson this afternoon. Calm winds with some pretty aggressive sustained gusts that mostly came out of the west. Made for some intense crosswind crabs. The skies were beautiful, the field freshly cut!

I met John flying electric, nice guy, welcoming, and a pretty good pilot. Fun to watch him goof off.

The 30cc flew wonderfully!

During a highly crabbed crosswind I learned where the east edge of the east side runway is... I started to set her down knowing I was off center but would be over the runway soon, and to my surprise she started to disappear! I realized she was UNDER the runway! The whole field is on the curved top of an old landfill. The east side runway has the road that leads up to the field on its east edge, and its about 6-8 feet below the runway. From where I was standing I can't see the road, just the edge of the runway. Nosed up, landed fine up the side of the steep hill, but grounded the prop. No other damage. Changed it out when I got home.

The RCGF 10cc ran well! No issues.Had a lot of fun!

On the thrid flight, another crabbed landing. Didn't get the tail around fast enough at the touchdown and the torqued the gear off. It wasn't super secured on the front edge... Beginning to think that its my thing.  Fixed it easily at home, No other damage. I did secure the front edge with a single small servo RTL Fasteners servo screw. It will hold nicely, but give under a good force keeping it from ripping off the bottom of the aircraft but giving me some resistance on tough landings.

This interesting thing happened. Twice at the field, so I grounded her and didn't maiden. When I got home I trouble shot it and realized it was acting like a power loss to the receiver. I was suspicious of the Receiver pack... I think charging my NiMH at 1C has caught up with me. I used another old pack and it worked just fine. Ordered a new pack. I have to admit I wasn't eager to maiden her in the crosswinds. If this had happened in the air it would have been disastrous. Damn lucky!

Can't wait to fly again soon!

Warner Field, SNHRCC, Hudson, NH

Southern New Hampshire RC Club, flies from on top of an old landfill, at the end of Old Landfill Road, in Hudson, New Hampshire. Its a bit of a drive from my home, about 23 miles, while the Southern New Hampshire Flying Eagles field in Merrimack, NH is about 9 miles from home. But its mostly freeway, so it takes about 30 min.

It was a drizzly and occasionally rainy day today, but the winds were calm in Hudson, and when they came up it was a nice crosswind from the east, consistently. I drove out, expecting to be the only one out there, and I was. It was perfect for me to get used to the field's edges, and how the aircraft look as they make approaches from the different directions. This pic is from the inner gate, on the road that winds up to the top of the landfill, up there.

Drizzly. Looking over at the West runway, electric and gliders.

Looking North. I am parked in the area between the runways.

The Alpha on the field looking to the south, on the East side runway, gas/glow and electrics on this side. This side is more expansive and just seems to go on, and on. The grass needs cutting and the field is pretty clumpy. The grass took the paint off the prop of the 30cc sized MX-Bach.

Standing on the runway, looking east.

Mud day. This is after the first flight. By the time I was done it was dripping in thick mud.  All of them were.

The Twinstar. I flew her 3S, and not unexpectedly she flies lighter. 4S and she's heavy but flies well. I prefer the 3S, but need to get more than 2200 mAh, as that flies about 5-6 min. The 4S is a 3300 mAh and gave me more than 10 min. The front gear that bent so easily on the first Twinstar also bent easily in the clumpy grass at Warner.

The 30cc sized 10S electric MX-Bach. The Sbach wing has the same bad habit of stalling in slow turns on approaches and dropping the inboard wing suddenly and sharply, even with flaperons set up. I ordered some L angle Styrene to make vortex generators, and will make those and install them in the near future. It will be interesting to see if this bad habit is fixed, or I will just have to make those sharp turns at speed.  You can see the missing paint on the prop. Will need to repaint and re-balance.

I flew all of these! I left 2 4S batteries and one 3S battery unused in the box. One of the 3S batteries, a blue Turnigy one, decided to increase its internal resistance into the useless zone, but other than that, this is 2.5 hours of flying one after another.

I prefer this field. I like the openness and visibility. The runways need grass work (I wish I could find those fields you always see in the mags with the putting green grass smoothness...). The club knows this and is working on a plan. Long approaches from both ends, more so from the north, and I prefer flying on the east gasser side. Merrimack is nice, especially with the geo-tex runway, but the entire flight is flown above the tree line that creates the hole you fly out of. Nasty steep approaches from the south, and tight approaches from the north, in Merrimack. I do like being there though, so will likely keep memberships at both fields for now. I liked having the aircraft back in front of me again, like I enjoyed at MCRCC in Gulfport, MS, where I learned to fly.

It was an awesome, rainy day, all by myself.

RCGF 10cc Muffler Adaptation

In order to get the cowl on the pipe on the muffler had to be trimmed about 1-2 cm. This short stack sprays the airframe with oil... I don't think it affects performance much.

On the 30cc DLE I used rc car muffler couplers as extensions and they work awesome. I found a couple of options for the Spitfire and tried them out this morning.

This is the full car extension, comes with a short coupler and the extension. The bent pipe is soft silicone, but is about 6 mm or so ID. The muffler pipe  on the engine is 10mm ID. Thats a 40% loss in diameter, and Poiseulle adroitly predicts a significant increase in resistance to flow (1/r4). I expected some significant back pressure and figured on some rpm loss.

This lasted 3 min. The solder bead I had on the muffler melted off as I expected it might, and the engine threw the extension and coupler off. She immediately gained the almost 500-600 rpms she lost due to back pressure. So much for that one...

So I went with just the longer coupler, and she runs fine. It gives me that 1-2 cm back, but I suspect there will still be some oilage. RPM performance is maxed, around 8200 rpm at full.

I hope to maiden her out in Hudson next week. Need a good clear, calm day.

Phoenix Models Spitfire with RCGF-USA 10cc V2 Engine Trials

The engine is installed and a couple of days ago I did the first start. I've been working to find its sweet spot as it breaks in, and I am coming pretty close. I then put the cowl on, and made a few minor adjustments. The weather had been damp and cold, so I expect to need some more tuning. I created a nice little hatch to allow access to the needles without having to remove the cowl.

Master Airscrew 13x8x3 prop.  I believe the spinner is 3 inches. I may replace it with a 3-1/2" if I can find one, notably a 3-blade. I just can't find one.

First start, since install. She was run months ago by Joe Nelson at RCGF-USA before he sent it out to me.

Full throttle. ~8400 rpms on these settings. She now tends to run around 7900-8200 full throttle.

Today, cowl on, done tuning. Idle around 2800 rpm, to full about 8100-8300 rpm.  Smooth transitions. On the DX8 I have a throttle curve set, no expo (it was screwing up the transition).

CG was curiously spot on.

Hatch to the needles. Wire handle secures against a wedge underneath the cowl.

I will wait for very good conditions to maiden her, and plan to do it at the SNHRC club in Hudson, rather than at SNHFE in Merrimack as I want wide open, though the nice runway in Merrimack beckons.

Spitfire Update: Pretty much done!

I've had to redo a few things, some a couple of times, but she's running and ready to maiden with a few adjustments.

Ready to start!

First run (Though Joe Nelson at RCGF-USA test started it before sending it to me). I had a lot of trouble finding the right settings for her. She runs great, but finding her tune spot was tough. To get a nice balance between high RPM and sufficiently slow RPM at idle took hours, of trial and error and I'm still not sure its right. Her high needle pretty much stays where it is, around one turn. The low needle which is tuned to get a clean advance from idle to high, changes everything including high RPM. It is the only needle I adjust, for the most part. That's odd. 

I used a Master Airscrew Scimitar 14x8 and a Master Airscrew 13x8x3, and with both get around 8100 RPM at full sometimes as much as 8400, idle around 280. The servo limits are at the stops for the throttle t about 115% high and 20% low. With the 14x8 I get about 6.8 lbs of thrust, and with the 3-blade, about 7.7. The plane weighs 7 lbs, so I am going with the 3-blade. She gives me over 20 minutes a tank at mid-throttle. I had to dial in a throttle curve to get a true 50% throttle, and a transition at low and high approximating 25% and 75%. All this spinning dishes... changing one thing changed another. I do think I have found her sweet spot. I suspect as she breaks in more, and when I get the cowl on she will need more tuning. I decided I need to create a hatch in the cowl to get to the needles. More on that later.

The left mount cracked during the break-in runs, so I had to replace it. I didn't want to re-grind one, since that's why it broke. So I decided to do it the way I should have, and cut out the triangle wedge that prevented me from putting it there. Later I noticed that the engine was pointing a bit left... so I replaced the right one, also grinding down the wedge, and now its straight and not MacGyvered.

The QuikFire was a tight fit, added weight, and I wasn't sure if the little engine could pull fuel through it making the tuning more difficult. It has taken a lot of time to tune her... She still idles a bit high. 

Cowl on!

I had to go through a couple versions of the choke arm.  Straight out works best. That's the cylinder on the plane's right side next to the cylinder. Works great!

Next will be seeing how things change with the cowl on, then maiden. I am thinking of doing the maiden at the SNHRCC field in Hudson, where there is more open space. 

In fact, I am hoping to head out there again soon. I rode my motorcycle out there the other day, and I like the field, first time I had been back in a year. I love the openness. Its a little further out, and it doesn't have the geo-tex runway, but the grass is short, even if it is a bit of a hill. Lots of room to fly, close in, and nice un-obstructed approaches.