kasper

Well for your purposes based on those wings I would say CL max will not be critical. If you are looking at a 300kg MTOW with something in excess of 12m^2 of total wing. Even discounting the rear winglift loss due to downwash and lower AoA when the front stalls you are looking at a landing speed in the 30's is my guess regardless of what section you use. Plug in the router, find a nice fat section that has low 1/4 chord pitch moment with minimal movement in moment with AofA that will allow you a good spar depth up at around 22-24% chord and plug it to the cnc and go.

Mr Benz ... Planey is showing his age and interests. For example The WWII Benz engines in the bf109/me109 were fuel injected and that was a functional advantage compared to the merlin carburetted engines in the spitfire and hurricane ... until the orifice was added to the carburetor on the Merlins ... google merlin and orifice if you dare 😉 Fuel injected engines are generally not impacted by neg G .... a carbi with a fuel float bowl will be ... the fuel pick up comes from the bottom of the bowl and in neg g that bottom is full of air so not good for engine running

Nobody has ever flown the Fraser section sucessfully in a flea. Plus that undercamber in the front is not constructionally easy to achieve in a farbric wing. I'll not attack the person but the single flea built with that section was wing sized to his 'claims' and hell it failed to deliver - big time failure to deliver. Very few people I know want to be in a very short coupled aircraft on small undercarriage going as fast as you had to to get that little monster off the ground ... I would not have been worried about the pitch moments but rather how little lift it achieved compared to the claims. The NACA section 23112 was on one of the HM293s I flew and it was no better or worse than the HM293 section on the original 1946 drawings from Mignet that I have flown the same day at the same airfield in France. NACA 23012 is quite a thin section ... the flea bike will not in honesty be a fast plane so a thicker section allows lighter structures for a given strength of greater strength of a give weight If you want to think about it the front wing is really a flying wing - the sectional choice open to you are any/all sections that have been used successfully in any flying wing that is not reliant on pendulum stability ... I'll point to to Martin Hepperle and his sections - google it. The sections he has designed are primarily for models but have been successfully used in a few man carrying flying wings - hang gliders and two different sailplanes to my knowledge. In terms of flying wing sections strange as it sounds the Horten IX jet from WWII has three rather nice sections - the mid span section has nice physical characteristics for fabric wing construction and was tested in the wind tunnel back in the late 40's ... technical papers on the section and the tests are available and can be used to compare to other modern sections (NACA sections are not modern .. they are just well published and available) John Ronsz has done a couple of sections used on flying wings and helicopters that you could consider but helicopter sections tend to be too thin to be constructionally viable in a flea. Lots of options. My HM293 under construction is using a section not previously used on a flea - I'm using a flying wing section - and that was chosen not just for low 1/4 chord pitch movement but the ability to put a light/strong spar within the wing at the chord position where I needed to.

Medicals are not the end of the world. Both ppl and RAAus are pretty ok on medicals. But you really need to decide which way your going now. You are up to the first closure on your fuselage and you really should be working with an inspector now and agreeing what they need to see and when. Plus what pics they want taken when they are not there but will be available when they do inspect. Call RAAus and ask to talk to tech office. They are operating remote so it will be a call back but they can and wil tell you what they will require even if you're not a member

And forum rules require not attacking a person but the topic. spacey had a run in with auf more than 25 years ago and has not acted on many offers of assistance to rectifying the issue he has. Raaus tech are Approachable helpful and well meaning. Unless you want to do something that is on the edge of what is permitted they are great to talk to and deal with. and to be open - I’m saying that from a position of having multiple run ins with tech office over the years and not particularly agreeing with the directions raaus tech seem to be going. I may disagree with them but they are good at supporting and helping get outcomes for the vast majority of items that they deal with.

If you intend to register it raaus then the costs during construction are similar for inspections if you find a friendly raaus person. More expensive if you go with a business running l2 who gets approved to do your inspections. Once it’s registered the annual costs are higher intbh longer term with raaus because you have membership plus registration annually. Once registered with casa your costs to operate year on year are lower IF you have your saaa maintenance course ticket. id ask the first question - what pilots certificate/licence do you have? that is a good clue which way to go. You can then decide to accept the costs or not. either way you should decide NOW because you need to get your inspections planned and the person sorted now. you should have an inspection before permanently closing any structures or any inspector is going to be less comfortable with what your are presenting.

Ish the throttle butterfly is the throttle because it is downstream of the Venturi and is restricting the amount of mixture admitted to the cylinders but not changing the mixture itself. A choke is a form of mixture control because it it upstream of the Venturi and regardless of throttle position it changes the air/fuel mix. in an aircraft engine the mixture control is actually adjusting the opening in the Venturi that is admitting the fuel. to put it against a common two stroke carbi - the Bing 54 from your rotax 503 and 582 1. The throttle is not a butterfly valve but the sliding barrel. And the throttle barrel has a tapered needle moving within the main jet off the bottom of the slide. Has the advantage of giving a more even mix change and volume change with throttle movement …. Two strokes are more sensitive to mix changes and have the ability to eat pistons with ease. 2. there is no choke butterfly and instead there is a secondary fuel transfer route that has a simple on/off stopper lifted by the choke cable. nice video and great photography

just like all the trike out there - variable hang points. Just be grateful I did not suggest an electrically operated hang point movement for the front wing - very nice on the trikes I've flown with that but it is a bit overkill for a single seat flea.

For me in a trike its a little more constrained ... I have laminated paper map in the knee bag with the plan in black chinagraph on it and use a red chinagraph on the clear plastic for actual - I can then see variance in actual from planned. I have the airfield plates or mud mad drawings with frequencies in the clear pockets on the bar mits and have a chinagaph on a lanyard attached to the mits to update or note running details on them - generally new frequencies/squark codes on left and QNH changes and fuel use on the right. On top of that I have a Avmap Geopilot II moving map colour GPS on the dashboard - its nice because its got nice easy to use with gloves on joystick and buttons - no touchscreen because I have yet to find conductive gloves that work on tablets and in open cockpit flying as gloves. I have been playing with a tablet and planning software but as I say in a trike I just can't get it to be as safe (not departing through the prop) and easy to use as chingraph and sleeved plastics. Over to the other trike pilots - what do you do for planning and flight progression management?

OK - I'll admit it, I am engaging in thread drift ... But as I have lived, worked and flown ultralights/microlights in Australia, the UK, the EU, the USA and Colombia I have had the joy of seeing local views and perceptions from a variety of perspective and in several languages. Many similarities on nationalism and national pride exist in all countries about their own systems/aircraft but it is a very clear difference have perceived in terms of the degree of nationalist view from within the USA to the rest of the world when it comes to ultralights/microlights/LSAs.

Well if you are reconsidering the wing ... All semi modern pous I have flown (14,290,293,360,1000,1100 plus non-Mignet pou layout) have an issue with the trim on the front wing. They nearly all have nicely put very low cp movement sections on the wing so up to stall the stick load is linear to angle of attack/load with a significant increase in load at the stall as the cp moves. BUT nearly all have put the pivot point in front of the cp and have a constant pull load on the stick. I have flown with bungee trim to restrict the stick load in the mid range of the flight envelope and also with a fixed trim tab on the front wing to achieve the same unloading of the stick BUT if you are looking at redesign and redo on the front wing consider exactly where you put that pivot point to minimise the trim load. Look at the graphs for your chosen section (or change your section choice) to put your pivot at a point that will be minimally in front of the most forward point the cp is likely to be at in normal operations - usually occuring when at minimum AofA. You will then find the pull force in flight much less of an annoyance than it otherwise would be. eg the HNM290FB has a pull force that is distracting for longer than 1 hours flight I think you will find the pull force likely to be less than ideal at 22% of chord pivot. To work out the expected pull force you will need to work through the entire airframe calcs as its one of the last numbers that pops out after you have worked through lift splits fore/aft and the sectional AofA for the selected airspeed. And as a reminder - the pou layout is a cannard and the rear wing is at a significant apparent AofA reduction due to downwash from the front wing so the actual load on the rear wing is amazingly low so you generally have to estimate a massive differential between fore/aft wing loadings/area. Have fun

I had 5 years instructing on Jabs, 912s and two stroke out of The Oaks last century so I am not adverse to Jabs in either engine or airframe ... but when looking at LSAs its a sea of 912's with the occasional 'other'. Hopefully Zoso will not up sticks and leave the forum but I thought it fair to lay out why his aircraft choice while valid for him is in my opinion an aircraft that almost nobody outside the USA would even look at.

Zoso, Sorry you're offended by internet forum robust and drifting threads using broad brush comments. But here is a summary view you may not like - the Vashon as an LSA is not at all attractive to the majority of potential LSA purchasers outside the USA for a variety of reasons. A few of those reasons are: 1. the engine is heavy, inefficient and hideously expensive. In the USA that may be OK because you have AVGAS everywhere but not ULP, you may have mechanics everywhere who will work on the engine but not the alternate (rotax??) and you MAY operate outside the 600kg LSA limits because you know its strong enough and nobody in the USA from the FAA are going to ramp check you and throw a shed load of $$ in hassle at you for breach ...NONE of those apply in Australia or Europe so people in those markets see a dinosaur engine that is expensive to buy, expensive to maintain and expensive to run 2. LSA MTOW limits are lower in other countries than the USA - Australian LSA operating on RAAus registrations are limited to 600kg ... the VASHON is basically a single seater with full fuel or two seater with fuel sufficient to be used in the circuit for training and VERY limited local flights. Hate to burst the bubble but the majority of LSA sales in OZ and Europe are not to training schools - they are to private owners. The Vashon without sufficient legs in terms of fuel is never going to be attractive to many private owners ... and the double whammy is that the schools in OZ run on a thin margin and an expensive plane to buy and operate is not going to be popular with the schools PLUS in training schools in OZ you will be hard pressed to find ANY airframe not flying a rotax 912. Sorry buit the rest of the world has moved on from the engine the Vashon uses. 3. Putting aside the low MTOW and fuel capacity of the Vashon in operations outside the USA the killer is that the overall performance is nothing new. It lifts two people for about the same number of hours and moves them at about the same speed as the Cessnas and Pipers from 20 years ago. And while yes the US$ price tag at around US$120k might look good to you that airframe landed and registered in Australia is going to be AU$190-200k ... and that price on an LSA with the operating limits the Vashon has is never going to grab a private buyers attention - its too expensive for the performance it delivers. 4. Europe and Australia and South Africa have for the most part stretched the LSA envelope: a. They are building VERY STOL capable LSAs without top speed but have the endurance through fuel capacity and lower burn that appeal to a STOL buying market b. They are building VERY low drag LSA with top speed and fuel capacity that gives them much greater range and endurance than the Vashon could ever achieve c. The very low drag LSA with great top speed have low stall speed because their wings are very well designed - not saying Vashon wing is not well designed its just it has a stall/cruise/max speeds that are nothing compared to other LSAs available. 5. A practical outside US killer is the engine ... people in Australia learn on Rotax 912 airframes and they BUY rotax 912 powered airframes ... the vast majority of pilots in OZ that have trained as RAAus pilots fly behind the same engine they learned on. The number who regularly fly an LSA with a different engine is minimal. In summary the Vashon will appeal to a tiny fraction of potential private LSA buyers outside the USA for one or more of the reasons above. And those reasons cannot be undone because they are at the core of the design of the aircraft. Nothing above says the Vashon is a bad plane or does not have nice features ... but they are valid reasons people, many people, look at it and do not give it a second glance. Now if the Vashon was NOT an LSA and it was sold on the features it does have it would be a vastly different assessment and you would not be talking to the majority of the members of this forum. If it was MTOW of 750-800kg AND had a float options AND you sold big time the ease of access and fold flat camping ability you would attract interest ... but it is an LSA and against other LSAs its not even interesting. If I was looking to buy an LSA with performance near the Vashon I would be looking at the Brumby Evolution 610: - same LSA design envelope - within a foot the same in any dimension (except wing area where it uses less to deliver the same as the Vashon) - same construction material of metal - but has a welded steel cage) - same high wing location - but has struts so is a lighter airframe for same strength - has same or better power in the 912 options - has 9 USG more fuel capacity than the Vashon - has electronic instruments as standard - can have options to bring it up to exactly the same as the Vashon - can be kit built if you want to do that - Vashon can't - can be tailwheel to take advantage of off field capability and bragging rights - Vashon can't Pretty similar airframes and performance ... but more than 25% less cost to buy than a Vashon, has the engine LSA buyers outside the USA want and for Australian its a local manufacturer so easier support. So Australian LSA buyers looking for performance akin to the Vashon have a MUCH cheaper local option. And even at that the airframe is not selling great numbers compared to other LSAs in Australia because in honesty the LSA buying market is skewed to the higher performance LSAs at similar cost or LSAs that work in the corners of the design envelope eg STOL. The Vashon works for you and your posts made clear a couple of the design points that make it work for you - no struts, low level easy access. However, the honest view from outside USA and in particular from Australia where this forum is based is that it is just another rather ho hum average performance aircraft that is actually very expensive for what you get.

Well that issue of getting the pivot on the cp or there about a is the reason fleas NEVER have the spar way back at 40% the spars end up front on the cp and the rear spar way forward at around 66%. flea pivot wings never need strength in the rear of the wing - there are no control surfaces and no twist forces from ailerons - but every Pou flying has a single lift/pivot spar at/just in front of the cp hate to say to you if it were me I’d use the ribs you have for the rear fixed wing as you can use the lift spar as the fixing spar but start again and redo the design and ribs for the front wing with the lift spar forward.

Design concern - your pivot spar is not your lift spar therefore you are expecting the full lift forces to be passed from the lift spar to the pivot spar through the ply ribs - I would reconsider that and use the same full span spar as both your lift and pivot as you are then not passing significant loads through the ribs Design comment - I am assuming that your pic omits the verticals on the ribs that will make each of the ply spar webs complete framed panels. Design comment - while its a hassle its not a big hassle to cut your ply spar webs on the 45deg - especially as they are small panels and you have a cnc you can use to cut them. that 45deg face ply orientation is significantly stronger that running the face grains along the spar. Design comment - having effectively a five piece wing does make the folded span really narrow but you are adding quite a lot of weight in hinges and pins. Why do you want it so narrow? if you are folding it to then road trailer it with wings on consider that the trailer loads on the fittings for a heaver wing up on thin struts will require additional support fixings which are a bugger to design nicely if you do not 'lock' the airframe undercarriage springing and just have trailer springing - a few people found to their cost that a trailered SV2 vampire with the supports on the wings managed to damage both the wing bolt points and the tail boom attach plates - both of which are a bugger to get to and replace. Operating comment - you definitely CAN achieve 6G in a flea ... you can also achieve over 100kns in a single seat flea with 40hp ... I did both when test flying a flea in and around all the corners of the envelope.

Never worry Spacey ... its the new century and the ELECTRIC Messerschmitt is starting delivery in Germany next month. Only 5kw motor and at best 90kph but thats pretty much what the original did and less smoke to do it. http://messerschmitt-werke.de/lang_en/kr_E.php

For marine use it’s fine … build some nice wooden floats for your flea … then you can be the first splashy flea in oz it should stay nice n cool in water. note - seriously I found that the white fabric wing was only 15deg c below the critical temp when the aircraft was in 32degc day full sun. In reality it wears ok as when flying it cooled down but I’d never have painted that wing any colour as that would have probably hit the critical temp and the whole thing goes a bit soft and droopy. changed over to west and the test pieces are brilliant and it is not just cheaper but easier to use than t88

Agree on the epoxies. I’ve built using t88, west system and boat cote. I’ve always done post cure heat treating and the only one that’s a not to use again is boat cote. The issue is the low thermal softening point even after post cure treatment. I used it to build a white fabric wing and the measured temp inside the wing was too close to the thermal point of the glue for my liking. west system is my favourite - it can be thickened with west system fiox and makes a great glue and it’s cost is half that of t88. my flea is going together with west on the wing and t88 on the fuselage just because that’s what I had when I built the fuselage. wish I had done routed ply ribs - I was over ply discs and the kit of sticks to make them … but they are beautiful to look at and weigh very little.

Hmmm. 600kg MTOW + 398kg Empty = 202kg for people AND fuel = far too heavy to be realistic/practical as an LSA. Even shedding 20kg with a rotax swap you are not left with enough to be practical - 1 person plus good fuel or 2 people in the circuit. Not gonna sell many with that as the operating envelope. And given the Australian requirements of Empty + set KG people + set KG fuel based on power to get into RAAus its not going to appear here at all.

In my thoughts of the future of fuel is it will be very mixed: 1. EV battery with charge at home/charge at public charge point (30-45min for 80% recharge is currently available) 2. automated battery swap out locations (in addition to 1.) - already exists in china - check youtube to watch it - 3 min swap for battery no human involved - requires manufacturers to agree ... not holding breath on agreement so will see multiple infrastructures 3. Hydrogen fuel cells and hydrogen combustion - will arrive and part of the fuel mix over time 4. Hydrocarbon liquid fuel from solar direct - already exists in prototype form and will arrive and part of the fuel mix over time - is a direct replacement for existing ICE engine There will be no single solution that fits all, I am expecting that my airframes will move over the either EV electric with reduced endurance (already preparing one airframe) or will convert to Hydrocarbon liquid fuel at a much higher operating cost than current liquid fuel but retain the range. Just my two cents

And from someone who built their own wiring harness for three micro airs and counting RFguy is correct. Side tone is the intercom on the radio and if you absolutely follow the wiring diagram they work. In one install I had to adjust the side tone pot - access through the hole on the side and adjustment is set out in the manual. check your wiring to the schematic and if it’s all ok you work through the side tone adjustment. or as Kyle comms says your alternate is don’t use side tone to intercom and add seperate intercom.

5 years till all the money is split between my fun stuff and husbands fun stuff - not ultralights. Still rebuilding other airframes and building my own for those five years and they are basically all ICE. But we’re into sell a 912 trike I could plug n play electric and I already have the solar on the roof of the hangar to charge so low cost single seat fun potential.

The true budget let’s make do and mend in me says grabs series 1 Nissan Leaf and monster it. The 40kw battery pack including bms is 240kg and that’s 48 battery units inside the pressed steel case. The 107hp motor is heavy at 58kg with the single ratio reduction but that puts the output shaft at under 2000rpm and it’s liquid cooled. all stripped out your at around 250kg of power system. That would be nice is a new - not retrofit - airframe that is designed around the spread out battery system and has low drag. 150kg for an airframe on top of that leaves 200kg for people In the current raaus area which would be a lot more endurance than the electric alpha. but I do not fool around with the 360vdc on my solar panel setup and I do not fancy the risk of reconfiguring the battery pack and all the gubbins into an airframe without an electronics engineer mate to stop me killig myself in assembling it.

Yes. 20 constant with 25 peak. Air cooled. It is a single out runner but if you want more power for larger aircraft they do duplex motors up to 40/60kw that are under 12kg for the motor … an air cooled 912 replacement that weighs 12kg and is under 40cm across.