Matchless Sentinel F3P

[matchlessaero]

I've yakked about this plane for a while, but its finally coming to fruition. I spent last week refining the drawings and the latter part of the week cutting and painting. Progress has been slow because of real life getting in the way, but I'm pretty pleased.

This airplane is approx 90% the size of my Kestrel 3D Freestyle plane. That puts it at a 30" span and 30" length.

My goal with this airplane was to design an airframe and figure a spec that would allow me to get to the weights that Fwilly has been achieving, but without going to the extreme of coring and rewiring servos. I intend for this airplane to have plug n play equipment for ease of use.

For power, it uses a BSDMicroRC Gold motor, a TB9 ESC, and an Etec 2s 300mah lipo. Reciever is a Berg4, and servos are the Blue Arrow 4.3's(whats in mine) or Dymond 4.7's.

When I popped it on the scale for the first time, I was pleasantly surprised to see a weight of 3.4ozs with all gear. I did not have the pushrods on the scale or the fuse/wing reinforcing thread, but that is a pretty negligible weight, so I believe I should finish it out at about 3.75ozs.

The lines are untested in the air, but the wing and horizontal are directly from my Kestrel. I should have an opportunity to fly it in an indoor facility on Wednesday.

I hope ya'll like it.

[RV6-A]

I hope PLANS will follow after test flights, I really like it. The kestrel flies so good I know this will be a great flyer!!!!

[Mike Williams]

Wow, that looks so cool. :)

[Jerry Combs]

Darn it, I still can't catch up with Matchless and FWILLY. This is my latest model, it is Tim H.'s F3X scaled down to 27", weighs 4 3/8 oz. Power is just a 22mm CD motor with a Thunderbird 9 and a 2s 400 Twenty Polyquest. Berg receiver and 303 servos, like Matchless this is all with stock connectors and wires. For the bracing I gave .5mm carbon rods a try. I would like to try one of your Sentinels someday.

Jerry

[racerxky]

I like the mid cord carbon spars. I think they provide the most bang for the buck. Best of luck with the maiden flight.

I'll soon have something else for you to build too. ;)

[matchlessaero]

Not bad Racer....

Ok. I finished my bird... and wow...I'm really happy with it!

First off, I ended up with a GWS Pico BB on Ailerons to get enough torque. Everything else is exactly as mentioned before. I tried some lighter weight battery connectors, (2mm kind) but they could not pass the current fast enough so off they went.

Final weight 105 grams/3.7ozs. I know where I can lose about 5-6 more grams, so I know I can get this little thing to 100 grams easily. I'm also really pleased with how stiff it is. No flex at all in flight- period!

Again, the other cool thing here is I did not do any special wiring of servos, or lightening of major components. Everything here is off the shelf stuff.

I could not stand it, so even though the wind is kickin along at about 10mph, I put her up for a test flight. It slows down very nicely, no coupling on KE that I can perceive, rolls are quite axial. I can't way to put it up in the gym and really critique it.

Heres a few pics.

[Malves]

Looks great, bro!:) Extremely light, too.:)

[matlok]

I've yakked about this plane for a while,

No pun intended, right! LOL

Looks great!

[aglenn]

Looking good.Cant wait to see it fly on Wednesday.....

[matchlessaero]

Thanks Malves and Matlok!! :)

One more pic... I put the aero-effect holes in the trailing edge. I'm interested in how they effect the flight characteristics.

[Jerry Combs]

Looks very good Jeremy. I will be very interested in your views as to how well the aero-effect holes work. I had hoped to get a chance to fly with you at SMALL but I am not going to be able to make it.

Jerry

[racerxky]

What do you use/do to make those holes so precisely?

[matchlessaero]

What do you use/do to make those holes so precisely?

Racer, I'm very good with an exacto knife! Just kidding. :D LOL

Seriously. I marked all the trailing edges with a marker and stainless straightedge. Then I used a sharpened piece of brass tubing to cut the foam. You simply rotate the tube while pressing it through the foam. I held a small scrap of ply behind the foam to act as a backing plate so the foam would cut better. :)

[fwilly]

Wow, it looks great!!

Hurry up and post some vid of it!!

[Brummeh]

I hope for my sake its 105 grms without the battery.... :eek:


Mike

[matchlessaero]

Mike, That is with the battery installed ready to go. :D

Fwilly, I should get some vid tomorrow evening. I'll try to put it up asap. I'm afraid my flying may not live up to the airframe's potential though.... :rolleyes:

[RV6-A]

Don't sell your self short, I've seen you fly ! Hope to see vid soon

[j_z_123]

Nice!!!

[racerxky]

Mike, That is with the battery installed ready to go. :D

Fwilly, I should get some vid tomorrow evening. I'll try to put it up asap. I'm afraid my flying may not live up to the airframe's potential though.... :rolleyes:

Uh uh, no excuses, get out there and huck it!

I can't fly well either (I'm on only me second R/C airplane). That doesn't stop me from trying to put the airplane through the basketball backboard! :rolleyes:

Flying these things is all kinds of fun and a great way to get into aerobatics.

Hope everything goes OK, looking forward to video.

[Jerry Combs]

I have seen Matchless fly, he is very very good. I am quite sure that he can fly the airplane as well as any.

Jerry

[Mister UHU]

Very nice work MatchlessAero !!!

The fuselage bracing ;
is it Carbon rods ?
or dental floss etc ?

And so light too !!!
Special motor ??

[Uttam1]

Hi Jeremy,

Looking great! Looking forward to the video :cool: Where is that motor again, I see only Depron and Carbon :rolleyes:

-Uttam

[matchlessaero]

Nice!!!

Thanks JZ!

Mister UHU, the bracing is round carbon rod. Billy Hell and myself did a how-to on it in 3D Flyer last month. The wing bracing is .040 carbon, and the fuse bracing is .030 or .020 (can't remember) all installed with foamsafe CA.

The motor is a Mighty Midget Gold, manufactured by noneother than Uttam (see previous post). Its available from BSDMicroRC.com here in the States. Uttam's website lists the vendors elsewhere in the world. Yes, the motor is special, but its an off the shelf item. By spending a couple of extra bucks on the right motor, I was able to use smaller carbon, battery, servos, pushrods, etc.

I had a very calm evening out yesterday so I put in another outdoor flight on the bird. Duration with the 2s 300 pack and the Gold motor is very good. The bird is extremely smooth in the air and tracks a line quite nicely. The aero-effect holes in trailing edge are more effective than I thought they would be- When you deflect a control surface, the plane slows down a good bit and you need to power through the maneuver.

Here's a pic of the motor...

[Aio_1]

The plane looks nice. Good work!
...I put the aero-effect holes in the trailing edge. I'm interested in how they effect the flight characteristics.
What is the intended effect or is it purely an experiment?
I've seen several planes using holes on the control surfaces like this but I'm still not sure what they are intended to achieve. There are potential effects on drag, flow control and and control response but I'm not sure which if any of these they are intended to influence.

Aidan

P.S.
I posted this before reading your last post. So they are intended to (and do)increase drag in manoeuvers?!
That's as would be expected but it might be worth trying a flight with them covered by tape to be certain the holes are responsible for the characteristics you are observing.

[Uttam1]

Jeremy, thanks for the kind words. What wind motor is this? 9/11T?

-Uttam

[matchlessaero]

I got to fly the Sentinel last night in the new facility (nice big place, but the end of it was approximately like flying in a single court basketball gym).

I think I have gotten the weight of the bird just about right. Wingloading 'feels' good in the air. Roll control is very good, pitch and yaw are just about what I wanted them to be, and the power to weight ratio is just right. On a full pack it easily does all the uplines crisply. No coupling to speak of in the air on KE, and no bias in the roll.

I had a little difficulty at first with pitch sensitivity. You can see it in the vid. The airplane seemed to 'hunt' a little bit in pitch at times. A quick examination after that first flight showed that I had drilled the elevator control horns too large and there was about 8 thou. of play in the control horn- just enough to make it 'hunt'. I fixed that problem for the 2nd and 3rd flights, and the improvement was very noticeable. I also plan to move the CG back slightly

I had ACGlenn give it a try as well. He seemed to get into the groove rather quickly with the bird and appeared to get comfortable really quickly with it.

Overall, I am very pleased with the little bird. Its extremely light on the wing, and holds a line very well when trimmed correctly.

Now, as for flying the pattern, I know I need a ton of practice... FWIW, I've never flown pattern before- I'm a former pylon racer transformed into a 3D'r. Part of my reason for wanting to try this is to get into precision flying in order to improve my skills overall and to sharpen up my 3D Freestyle skills.

I don't have the pattern memorized, but I remembered several of the maneuvers of the current F3P pattern, so I began working on them and some are in the vid. Oh yeah... I could not help myself and threw it into a hover a couple of times as well as kicking it around in a harrier. It 3d's fine, but thats not what I designed it for....

Here's the vid
http://www.theprofilebrotherhood.com/~video/Sentinel1.wmv

[RV6-A]

Nice video,it looks real good flying. I WANT ONE!!!

[Jerry Combs]

Jeremy,

Looks good! Very nice flying. What prop are you using and which wind motor?

Jerry

[Uttam1]

Jeremy, wow, nice video. The plane flies great :D

Uttam

[fwilly]

Looks like a sweet flyer!!

[Uttam1]

Hmm, my guess is it would be the 9T motor, and a 6*3 prop?

[matchlessaero]

Thanks Ya'll. After I've flown this one for a while, and figured out how to fly it, I'll put up another vid. :D

Uttam, I believe you are right on the wind of the motor and yes its a 6-3 GWS with the prop adapter that BSDMicroRC sells.

[Jeffery]

You got Stano hooked, and that's good....I just snagged another RZ 350 off him :)

Pretty good flying plane, Jeremy. You might amount to something yet! ;)

[Malves]

Very nice vid, bro. I liked it a lot.:)

[Mister UHU]

The motor is a Mighty Midget Gold,
manufactured by noneother than Uttam (see previous post).

Its available from BSDMicroRC.com here in the States.

Uttam's website lists the vendors elsewhere in the world.

Yes, the motor is special, but its an off the shelf item.
By spending a couple of extra bucks on the right motor,
I was able to use smaller carbon, battery, servos, pushrods, etc.

Here's a pic of the motor...


BSD website claims 200 gram thrust from an 8 gram motor !!!!

Amazing.

My 20 gram Microtex does around 200 grams.

The 30 gram Hacker does 300 +
The 25 gram Axi does around 300

Uttam your motor seems truly exceptional.
Have you discovered some new law of physics or something ?

[Uttam1]

No. no new laws of physics. The 200gms thrust is at 10V, and that's for the 11T wind. This is a burst rating however, We don't recommend it for more than 10 seconds, preferably in flight. Besides, the latest production motor weight, is not 8gms but 7.6gms. The results on our website are actual, obtained on static bench tests.

-Uttam

[fwilly]

You would have to see Uttam's motors in person to understand how he can get those results. They put a Microtex to shame.

[Jerry Combs]

You would have to see Uttam's motors in person to understand how he can get those results. They put a Microtex to shame.

I haven't seen the Microtex but I can say that Uttam's motors are works of art. I have had one of his 10mm motors for a while now and I am still amazed at the workmanship and power of the motor. I am looking forward to getting one of the "Gold" series motors in the future.

Jerry

[fwilly]

Its been a while since I've seen a Microtex, but to me it just looked like a 20mm cdrom with a machined bell and bearing tube.

[matchlessaero]

Yup, Uttam's motors are well worth the money. They are assembled very nicely, and they perform as they are reputed to.

I am convinced now that this (or something similar) is going to be the optimum setup for American gymnasiums. At the ETOC, I was talking with Benoit D. and he commented that Euro facilities were almost always larger with higher ceilings, and they did not have obstacles such as basketball goals hanging at the ends, therefore they had more 'room' to fly in. Because of that, I think in the USA, we'll need to have even better performing birds to handle the more cramped environment than our Euro counterparts do.

[3d Dave]

Matchlessaero,
I am very impressed with the weight of your plane. I have been working on the shocky yak 54 to see how light i can get it. So far Ive got it down to 152g auw and that is using almost no carbon. Kevlar truss bracing, single carbon wing spar, and 1.5mm carbon landing gear.How are you getting it so light?? It got to be the motor battery combo that does it? Your plane has loads of carbon so whats the secret? I have the 26g mtr and a tp480 2s. Can you post the weights on you set up? Thanks. Oh yea that vid was awesome!!!!
Dave

[Uttam1]

Hmm, lets see, ~11gms for the motor, prop, mount and adapter. ~22gms for the Battery pack, ~5gms for the Berg RX, 12.6gms for the 3 BA servos, ~4.5gms for the CC TB9 BL ESC, that makes a total of ~55gms for the entire equipment. That leaves around 50-55gms for the entire airframe.

-Uttam

[Alexandre Cruz]

He uses a E-tec 300 2S that wieghts only 17~18g so ~50g for equipment, all I can say is that the airframe is waaay too heavy :D

Matchless, are you going to post any plans? I really like the video and I´ll try to do something like that, my owndesign 28" YAK weights 112,5g using a gb motor (unfortunatelly taxes in Brasil are too high to import a Uttam motor), may be I can get it 120g or so.

Thanks

[matchlessaero]

Dave, Uttam got pretty doggone close with his listed weights. (thanks for posting them Uttam : ) The other key to the light weight is to only put things if and where they are needed. For example, I know the motor you run will put out much more thrust, but its useless thrust for indoor pattern, so I run a power system that does not put out as much thrust- only as much as necessary to complete the routine correctly.

Weight savings is a 'domino game'. I run lighter gear, so I don't need as much bracing on the wings and fuse as they don't have to withstand the same loads, Landing gear can be lighter, and I can run lighter pushrods. As you make one piece lighter, don't forget to adjust everything else : )

Alexandre, I may post plans, but I want to refine the plane a little more. I know I can get more weight out of it. I think it would also be of value to get it into a competition at some point soon to find out how it really compares!

[Jerry Combs]

Dave,

Some weight savings can be realisized by being very careful when applying glue, glue is heavy, especially CA and epoxy. Tape will also add a weight. I use several short sections of tape for hinges rather than running tape the full length of the surface and I use no tape over the carbon reinforcments. A friend and I built identical models but there was over an ounce difference due to different uses of glue and tape. The friend comes from an outdoor slimer background and I come from an indoor rubber powered microfilm background. The friend built to survive crashes, I built to survive flight loads.

Jerry

[Aio_1]

...The friend built to survive crashes, I built to survive flight loads.
Don't forget that often building to survive crashes has the very opposite effect! It may not apply so much to these indoor planes since their structure is so minimal.

Aidan

[fwilly]

Yeah, my really light planes survive crashes pretty well, with the exception of mid airs:eek: My latest plane has so much kevlar thread, that if anyone midairs me, it will take forever to get the planes apart.

[matchlessaero]

Yup.... I dorked this one in nosefirst on the driveway just after its maiden flight. The airplane did not have enough momentum to break anything...... Keep it light- it will fly right!

[enigmabomb]

Matchless,

Please, please please more details how you braced the wing without gluing carbon to the LE and TE. Looked like it flew exceptional.

Finally, I hate to be "that guy" but putting an extra aileron servo would be totally beneficial. It's only 6 or 7 grams. If you take your wing area, and calculate the change in stall speed by adding 6 grams, you'll be pleasantly suprised. At 30 inches, you almost can't afford NOT to add the extra servo. Think of the benefits, aileron differential for super locked in rolls, flaps, spoilers, etc. You might have been a little tail heavy anyway, so the weight up front might help.


Thanks for sharing.

Josh

[Aio_1]

I'm not sure that there's much benefit to flaps or spoilers on an F3P plane. You could couple the flaps with elevator to tighten the pitching response but I'm pretty sure that's not necessary. You could fly slower but only in "straight and level"-ish flight. During manoeuvers the flaps would reduce aileron response and also cause coupling problems. Aileron differential will only be needed and helpful if the plane is badly designed for F3P. If purpose designed for symetry differential would be detrimental. Differential is used to minimise adverse yaw but these planes tend to spend as long inverted as upright and differential would increase adverse yaw while inverted.
I think 3 servos is plenty. 4 makes for simpler connections and easy trimming but it adds the weight of a servo and requires a 5 channel receiver. I doubt it's justified.

Aidan

[enigmabomb]

Aidan,

Do you fly precision aerobatics? Almost every plane needs some kind of aileron differential to roll straight. Adverse yaw is when a plane is turning it needs opposite rudder, that is not what we're talking about here. I'm simply talking about the aileron going up causes too much drag and the one going down doesnt create equal lift. This causes a 'barreling' in rolls. Making them present poorly.

Not to mention the whole issue of why not have perfect 90° linkages with two servos or one really cockeye linkage with one.

Josh

[fwilly]

There are ways to put diferential in mechanically with one servo, if you have to have it. 90° linkages aren't too hard to do with a single servo.

That extra 6g also goes against your power to weight ratio.

OTOH, if you had two good 3g servos (please, if anyone knows of any LMK) it wouldn't be a bad deal. A Berg 4L can be modded to get ch 6 with minimal weight gain.

I'm atattching a pic of the drawing where I figured out the aileron linkages for one of my designs. To get differential, you would have to change the angle of the aileron arm, and adjust the linkages, to re-level the ailerons. Just like adjusting it with a radio, it would have to be trial and error. An arm with an adjustable angle would be needed for figuring out the angle, but once you've got it down, a lighter fixed horn would be possible.

I'm still not convinced differential is needed though. Once you get inverted, the differential is reversed, and if you plane is realtively symetrical, then your roll coupling will be worse.

[racerxky]

I have read somewhere in this forum (or perhaps it was Jurgens blog) that the French/German F3P pilots find the 6g servos are more precise than the 4g servos. So i think the first choice is wether to use 6g or 4g servos.

I haven't tried any 4g servos yet but I doubt very much that I, personally, could feel the difference in responsivness. I would like to stick with the 6g servos just to keep things bullet proof though, especially with those big biplane ailerons.

That said:

4 servos * 6g = 24g
3 servos * 6g = 18g
4 servos * 4g = 16g
3 servos * 4g = 12g

Then you could mix-n-match; one 6g and two 4g. Four 4g servos might make a really good combo on a biplane. For a smaller monoplane, like what Matchless has here, the three 4g servos are a good match.

[enigmabomb]

Fwilly,

Please direct me to the Berg4L Modification. I'm interested to see how that is done. Also, regarding mechanical differential: There is no reason you couldn't do it that way. I'm totally on board with that program. However, the ease of 2 servos is worth it. Also, consider the linkages and sub trim involved. PIA.

I'll be sticking with my two servo setup. And if anyone would like to fly my plane with and without aileron differential to see the difference, I'm totally about that. I dont go to that many events but if I'm at one, hunt me down. Im all about passing the TX around.

Finally, on the inverted logic. It sounds good, but the problem ultimately remains the same inverted. One aileron is making too much drag. It doesnt matter whether its inverted or knife edge or right side up. Differential fixes this problem. All you're trying to do is create equal forces.

Regarding 6g servos, I have no problem using 6g or 7g servos. A nice tight gear train, good linkages, and excellent centering are worth almost any weight penalty. In the case of 2g per servo, I'll take that any day.

Just my .02.

Josh

[fwilly]

I'll have to take some pics of the Berg mod. I just poked and prodded around with a multimeter until I found which chip the servo signals were coming from and then tested different pins until I found 6.

[Jeff Pfeifer]

Looking good Matchless, and Fwilly! I should have some new stuff for next indoor season!

[matchlessaero]

Thanks Pfeiffer! Can't wait to see what you come up with.......


Yesterday evening, I had a chance to try some of my new battery packs, and the clear winner in this size is the 'Twenty' 2s 300mah. Without adding any weight (1 gram extra) I now have pleny of power to give a light 'punch' to pull me through a balked maneuver.

I'm finally starting to get the little thing dialed in as far as CG is concerned as well as the control throws to make me most comfortable flying the plane.

Before I went to the indoor facility, I wrote down the F3P maneuver schedule and practiced it as much as I could while in the air. I got to the point of making it approx 1/2 way through the schedule with little difficulty - Airtraffic kept me from getting all the way through each time : (. I also practiced every maneuver in the schedule as well. Personally, I need practice on the 1 roll rolling circle from inverted, and the top hat with quarter rolls. (the top hat gave me fits.....)

Several other people tried out the Sentinel and they all seemed to feel good with it. It flies approx 2/3 the speed of a 5-7 oz foamy, which makes a huge difference in our American sized gymnasiums.

I have decided that I won't use the BlueArrow servos again. They have proven to be fine in a 'fun' foamy, however, they don't center well enough to compete with IMO. I'll be moving to Dymonds next....

[Trisquire]

.......I got to the point of making it approx 1/2 way through the schedule with little difficulty - Airtraffic kept me from getting all the way through each time.......
I wonder how the Europeans get all the way through the schedule. I suspect they just take turns flying.

Tom

[Uttam1]

Jeremy, Have you tried the BMS 303 servos? I've had good luck with them, and they seem to center nicely.

Good on the 20C 300mah lipos. Have you tried the True RC 350mah Lipos? http://home.comcast.net/~truerc/ready_pack/ready_packs.htm

-Uttam

[racerxky]

It is certainly a lot less stressfull to fly solo. I try to avoid flying when others are up in the air. Just wait till they have to switch battery packs, or they crash ;).

[matchlessaero]

I love to fly solo, but we're trying to increase attendance at our events to reduce the cost for each person...... : ) We talked last night about forming an indoor club and each plunking down x -amount so we could lock in the facility 1-2 nights a month for the rest of the year...... I hope this goes through.....

Uttam, I've had such a terrible experience with the 303's that I don't think I'll use them again..... The Dymond D4.7's seem to be doing well for some people. I saw them on several planes at the ETOC as well.

[Bryan Davison]

MATCHLESS.

I know what you mean about the tophat...its a really simple maneuver that for some reason eludes me too. I seem to be fighting it at the top.

Its too much for me to try to fly the entire sequence. So what I am doing is practicing just specific maneuvers. I figure if I practice each maneuver till I have it down really well, then I can just combine them into a complete sequence. For some reason Im having a lot of trouble with the loop with 1/2 integrated roll. There's not much altitude in our gym. I have to do the 1/4 roll 180 turn 1/4 roll really low or else Im in the rafters in the loop because I entered it too high. Ive been doing 1/4 roll right, push 180, 1/4 roll left. I think it looks better when its a push instead of a pull. Seems to be easier too.

We really need a larger gym. I have no doubt I could do a fairly decent job of it in a larger auditorium. Trying to fly it in a basketball court with 20ft ceilings is a :censored:

Try setting up your one roll circle with the plane starting close to you, and ending close to you, instead of starting it from the back side coming towards you. For some reason its easier for me to do it like that, and I can get a pretty decent clean maneuver.

I think its just practice and TONS of it. This is not an easy sequence to fly. It makes the sportsman AMA pattern look like a cakewalk. Its still easier than the FAI P-07 sequence....sheesh...I watched Tony Stillman try to fly the P07...I was calling the maneuvers for him while he flew them. UNREAL.

[matchlessaero]

For some reason Im having a lot of trouble with the loop with 1/2 integrated roll.

In all honesty, the reason you are having trouble with that maneuver is not the size of the gym its the speed of the airplane (which is directly correlated to the size/weight).

You did a great job on your ICE. Very nice, light clean build, but I'm even more convinced now that a 6oz (or more) airplane with a wingloading similar to your Ice or my competition Kestrels is not going to be competitive in a typical US Gymnasium. They are just too 'big' in the way they fly to be competitive in that confined space.

I genuinely believe it will take an airplane with an overall loading like my Sentinel to be competitive in a typical gym.

You're 100% right about practice..... Time to go get some more in......

[Mister UHU]

Have any of you seen the Micro Yak kit designed by Benoit PLR ?

Should come out around 100 gram.

I saw CPLR's one recently,
he was using one of the Flyware Microrex 11 gram super motors.

I don't think it possible with current technology
to make a full performance aerobatic model much smaller than this.

You are really limited in your choice of RXs, servos, LiPos, ESCs, props, etc.


For small gyms you are always going to be compromised,
in what you can fly, and how you can fly it.

The smaller and lighter the model,
the more it is affected by turbulence from other models.

[fwilly]

The only thing really holding us back from getting well below 100g is servos. I built a 27" WS 3oz (84g) plane using 3.6g blue bird servos, but the servos didn't center well, and the gear train was sloppy.

Wes Technic has some 3g linear servos that look like they might work, but $40 a servo is too much for me to risk on servos that aren't proven for aerobatic planes.

The Falcon 1.7g servos are great for WAY below 100g

[Mister UHU]

It isn't just the servos.

You need good RX, with interference rejection.

Quality ESC for brushless motors, that is lightweight.

And small LiPos, of high power, and lightweight.

And the good brushless motors are damn expensive and rare.


You have to build really light, and so accurately.

And as soon as you have a mid-air with some other plane(s),
you have to repair or re-build.

Added to this all the odds and ends like wheels, control horns,
carbon tubes, are uncommon. And models on the limits are a bit of a pain.

[fwilly]

Berg 4L: 4g advertised weight, but can be lightened

Phoenix 10: 6g advertised weight, but can be lightened

Etec 250 Wes 310 Etec 300: 11-18g for 2s

Mighty Midgets, Microrex, cdrom conversions: 3.5-?

Could list half a dozen servos in the right weight range, but none work well enough. All the other stuff I have used, or seen in use. The motors can be expensive, but they're out there. I've got a 12g cdrom that was cheap to make.

Wheels and control horns are easy to make, and carbon comes in pretty small sizes, if you even need much carbon.

less than 100g might be a pain, but its very possible, even with heavier servos.

As an example, I did this (http://www.rcgroups.com/forums/showthread.php?t=184007&highlight=cap) over 2 years ago. It weighed 88g and used GWS pico servos, a GWS RX, a 20g 2s 340 pack, a 15g motor and a Phoenix 10. Matchless's Sentinel barely weighs over a 100g and its a normal sized indoor plane.

Mid airs are never easy on any plane that is built to fly...

[Trisquire]

Lets assume that we have the venue to ourselves. As you reduce the size of a plane, is there a point at which performance begins to suffer? Larger planes typically fly more smoothly.

Tom

[matchlessaero]

TriSquire, you nailed it with your question....

My goal (and IMHO what everyone's goal who is flying F3P should be) is to build a lighter airframe, not a smaller one. I've settled on the size that I'm flying because it presents well in a gym, has good moments and is structurally stiff enough with 3mm depron to fly precisely. The Sentinel is roughly the size of a gen1 Shocky.

Building a smaller plane (like the BPLR Yak from HL) just gives you a more heavily loaded airplane with shorter moments- in essence, you just get a 'handful' in the air, not a smooth, precise airframe capable of doing the routine well.

To add to that, I'm not worried about flying through other people's wakes as you don't fly F3P with another person in the air. Same goes for mid-airs.....

This project for me has been purely about indoor precision performance in the confines of a typical US gymnasium, nothing more, nothing less.

Oh yeah... (referring to MisterUhu's question) my other goal with this project was to do it with off the shelf equipment that did not break the bank..... I did that here for sure. The motor is the only pricey piece, but its worth it as the reduction in other costs makes up the difference....

Motor $91 (Mighty Midget Gold 13mm double, 9turn)
Servos $ 18ea (qty 3) (Dymond D4.7's or Blue Arrow 4.3's)
ESC $29 (Castle Creations Thunderbird 9)
Battery $17 (Twenty 2s 300mah)
RCVR $34 (Berg 4L)

Add it up, and you have a competition level airplane for no more than a typical foamy....

I'm genuinely hoping that others will follow my lead and do their own lightweight setups to fly indoor pattern with.

[fwilly]

I'd like to try a mono at around 25". I think that it would work well for the really small gyms. At that size, the wingloading needs to be lower than 30" plane to fly at the same speed. Even if they fly at the same speed, the smaller one will always look like it going faster, so it would need to be even lighter to look like its flying the same speed. It would definetly be more challenging to get it to look like its flying at the same pace as a bigger plane, but I think a smaller plane makes a gym feel bigger. In a small gym your forced to fly closer in so how it presents isn't as much of an issue.

Thats about my lower limit for F3P though...

[racerxky]

I like the low cost angle. I'm trying out the BMS 306 servos, they are cheap as chips and Bernoit used them so thats says something. (You can save a gram by taking the bottom of the case off too!)

Anyhow I see this class of RC as a gateway drug to get people interested in the sport. Its cheap to be competitive. Its very approachable. Its challenging. You can get a pro F3P setup for less than the cost of an XBox 360 or PS3.

Good time to be in the hobby.

[3dflyindan]

here here :D

dan

[Aio_1]

....My goal (and IMHO what everyone's goal who is flying F3P should be) is to build a lighter airframe, not a smaller one. I've settled on the size that I'm flying because it presents well in a gym, has good moments and is structurally stiff enough with 3mm depron to fly precisely. The Sentinel is roughly the size of a gen1 Shocky......

........To add to that, I'm not worried about flying through other people's wakes as you don't fly F3P with another person in the air. Same goes for mid-airs.....
I think it might be well worth reading Bert v/d Vecht's comments (http://www.rcgroups.com/forums/showthread.php?t=475395&page=6&pp=15)regarding optimum weight (and wingloading) for these planes. Apparently he ended up putting ballast in his 89g Shockwave design to get the flight characteristics he wanted. The comments are in a discussion about the choice between biplanes and monoplanes but they are very relevent to this discussion.

I hope this is of interest.

Aidan

[Aio_1]

Motor $91 (Mighty Midget Gold 13mm double, 9turn)
The 12g MicroREX Flyware motor is cheaper than this and appears to be competitive as it appears regularly in Jurgens lists. I think it's about €55 which would be ~$70. Not sure how easily available it is in the US.

[matchlessaero]

Aidan, I did read Bert's remarks, and they are very applicable. The benefit in building a lighter airframe is in the fact that you can then add weight where you want it. IE, since the servos I am using are not precise enough, I could concievably go with a heavier more precise servo.

The MicroRex does sound like an interesting alternative. Not sure of a US source, but it still sounds interesting (been reading about it for a while).

[Jerry Combs]

The 12g MicroREX Flyware motor is cheaper than this and appears to be competitive as it appears regularly in Jurgens lists. I think it's about €55 which would be ~$70. Not sure how easily available it is in the US.

Aidan,

The MicroREX is cheaper but by the time that we (in the USA) add shipping it is not that much cheaper. The Mighty Midget Gold 13mm double, 9turn is new and has not been used in any of the European competitions as yet as far as I know. We do not have easy access to some of the equipment ( just as you may not have easy access to some of the equipment that is available here) so a lot of us are feeling our way and finding out what will work for us.

One of the gyms that I have access to has a ceiling height of less than 18' (5.5 m) and is quite small at 50' by 80' (15m by 24m) so I had been exploring smaller airframes to suit the size of the flying site.

Jerry

[Mister UHU]

I think it might be well worth reading Bert v/d Vecht's comments (http://www.rcgroups.com/forums/showthread.php?t=475395&page=6&pp=15)
regarding optimum weight (and wingloading) for these planes.

Apparently he ended up putting ballast in his 89g Shockwave design
to get the flight characteristics he wanted.
The comments are in a discussion about the choice between biplanes and monoplanes
but they are very relevent to this discussion.

I hope this is of interest.

Aidan


A few weeks ago I saw a really lightly loaded 3D plane fly.

And while it was very controllable, and did very small loops etc,
it just didn't fly like a traditional aircraft.

It kind of flopped around, like most planes do when their CG is too far back.

While the BPLR MicroYak may be too small,
at least it will fly somewhat scale-like as the full size original.

I will be interested to see how the new MANTA kit turns out,
and how much better it is than the Ikarus Shocky.

Martin Muller seems good at finding the sweet-spot with his designs.

[matchlessaero]

I understand what you mean MUHU, but thats not the point of this forum or this thread. The point is to fly a prescribed routine as precisely as possible.

Regarding the Manta vs the shocky, its again an invalid comparison as they are really designed for two different kinds of flying.

[Bryan Davison]

Matchlessaero,

Dont overlook the shockies. Even though they are older designs, and many of them are scale aerobatic planes, ....they are still VERY viable entries for indoor flying including F3Ai.

Ikarus's F3A plane when built lightly, is a really smooth flying precision plane.

Also of the lightest weight planes reported...a BIG majority of them are Ikarus airframes or based on the Ikarus designs.

Ikarus shockflyers will go down in history with the other well known models. Aged as they are, they are still some of the absolute best flying planes out there.

[KNUFFAN]

Yep,

The Superstar and Yak planform are hard to beat.

[Mister UHU]

I understand what you mean MUHU, but thats not the point of this forum or this thread.
The point is to fly a prescribed routine as precisely as possible.

Regarding the Manta vs the shocky, its again an invalid comparison
as they are really designed for two different kinds of flying.



Sorry Matchless, I didn't mean to upset you.

How's your model ?

[matchlessaero]

You certainly did not upset me Mister Uhu, no apologies are necessary.

As for the Sentinel, I got a chance to fly it again in our indoor facility late last week. I have decided that the Blue Arrows are just not good enough for this application, so I need to order some Dymond D4.7's to replace them. Weight is just almost identical, and reported centering is much better.

[Mister UHU]

You certainly did not upset me Mister Uhu, no apologies are necessary.

As for the Sentinel, I got a chance to fly it again in our indoor facility late last week.
I have decided that the Blue Arrows are just not good enough for this application,
so I need to order some Dymond D4.7's to replace them.
Weight is just almost identical, and reported centering is much better.

Thanks, glad no offence taken.

I bought one Blue Arrow servo, was worst servo I ever bought.
Was defective, would glitch in opposite direction to control input EVERY TIME.
Didn't even bother to try and fix it.

I don't intend to buy any Blue Arrow stuff unless only option,
and proven to work well first.
"Try before you buy"

Dymond looks good choice, probably the best choice.

[Aio_1]

Dymond looks good choice, probably the best choice.
Yes the dymond 4.7g servos (sold here as Ripmax SD100) are very nice. They definitely seem smoother and more precise than others of the same size. I have a couple but haven't flown with them yet. The supplied servo arms are very small but it's easy to extend them with a piece of carbon or glass fibre board.

Aidan

[matchlessaero]

Thanks for the info Aidan. I'll have to get my order in soon.....

Its funny, usually my new prototypes are destroyed after a period of time or just plain worn out. Therefore I get to make revisions and changes and move on with the next one. However this bird has not died yet.... Its still just as nice as the day I test flew it...

I've decided I may have to build a 'jig' to assemble my foamies in the future. I spent some time checking the alignment of my current Sentinel and looked for things out of line. I did find that one wing panel was somewhat out of alignment(warped) and ended up adjusting it back to square. I think with a simple table type jig, I can get these perfectly square and warp free everytime. It should at least be better than using the edge of my workbench like I currently do....

[Aio_1]

I find I can build depron planes nice and square but they aquire odd bends and twists in the car or sitting in the workshop. Depron seems to shape a little too easily!

[matchlessaero]

Aidan, I've had the same experience with my planes sitting in the car..... On those days that I have to leave the airframes in there, I try to park in the shade...

Anyways, over in the Breeze thread, we were talking about the leading edge doublers on the Manta design by M. Mueller. I had noticed them some time ago and wanted to build another Sentinel with a similar arrangement. This morning, I decided I could not wait, so I went ahead and modified my existing Sentinel.

I believe it has made a change in the way the airplane behaves in pitch changes. I'll know more after the next indoor night.

[Aio_1]

I'll be interested to hear your verdict on the effects of the LE modification. I would expect it to be a little smoother in pitch, probably with less speed change entering loops etc, but that's just theory.....so far.

[matchlessaero]

I've flown the new leading edges a bit, and so far I really like them. I think the stiffness benefit is as good as the aero benefit.

Next up, I decided to try the aileron drag spades found on MM's Manta. I went with a slightly different shape, and a different size, but I think they are quite obviously influenced by his design.

I put 3 flights on the bird, and I do like the way the spades have affected its flight characteristics. Rolls feel a bit more axial, and the downlines are slower. I may try an adjustable pair on the next one.

Here's a pic.

[dawsonh]

Wow! What a fantastic plane.

I just stumbled on to the F3P forum and am amazed. I am mostly a slope soarer and love to to acrobatics (close to the ground). I have had a couple 3-D style planes but only fly them when there is no wind (not that often here). I am not really that into the "hang on a prop" style of flying. But your Sentinel really flys!

I am going to order the Kestral plans, get some Depron and start cutting. I have a 2204/54 and some small batt packs I can use for now, but that BSDMicroRC Gold motor seems to work great for your design.

I'll let you know how things turn out.

Thanks,

Dawson Henderson
(looking for indoor flying spots)

BTW... I loved your video (Joe Satriani is one of my favorite guitar players).

[matchlessaero]

I'm glad you liked it Dawson. Thanks for the compliments.

When you build the Kestrel, let me know. I have some new tricks to improve the plan that came out in the magazine. Simple stuff that makes it perform better.

Your 2204-54 will be great on it and it will fly well.

The BSD motor is wonderful on this airframe, but it pays to build it light. I believe this will be my competition motor (Indoor Pattern) for a while.

(Satch rocks!)

[dawsonh]

Just wondering... are you using the 11 Turn (mild wind) or 9 turn (hot wind) Gold motor?

[matchlessaero]

With the Sentinel, I'm running the 9 turn 'hot wind' motor. I have a mild wind motor to test, but I've not done any serious testing with it yet. It may be more of a 3 cell setup, but I won't know until I run it (or maybe Uttam can pop in and let us know..... Uttam, calling Uttam....?) :)

[Uttam1]

Jeremy, actually, the 11T "Mild wind" motor runs nicely on 2 cells too. Have a look at our website for results:

http://www.microbrushless.com/productsG3.htm

You might give it a go on your Sentinel, lesser Thrust, but much better duration.

-Uttam