admin (Simon W) Posted September 19, 2020 Share Posted September 19, 2020 What makes you use that calculation? Would you 'not' use Aspen in a 4 stroke then? If not, why bother using it in the 2 stroke? SW Quote Link to comment Share on other sites More sharing options...
chrsfrwll Posted September 19, 2020 Share Posted September 19, 2020 25 minutes ago, admin (Simon W) said: What makes you use that calculation? Would you 'not' use Aspen in a 4 stroke then? If not, why bother using it in the 2 stroke? SW Good point well made. Wasn't thinking that through. Doh! Quote Link to comment Share on other sites More sharing options...
Blackburn Mark Posted September 19, 2020 Share Posted September 19, 2020 3 hours ago, chrsfrwll said: I don't come close. However at 3l/hr I'm happy with the trade in simplicity and lightness, Its an old Bailey 175... All up with a full tank, reserve and flight deck is 45kg // And its a bit gutless. I can struggle to launch bigtime in light winds... massive disadvantage! A 30kg setup would be bliss but I just cant let go of the efficiency... its pretty reliable too. Last Monday, I flew to Malam cove with a guy who burned almost 15Llr in two hours... He only just made it back.He also owns a Bailey 175 and he hates its weight.... But he is tempted to give it another go or buy the slightly lighter Bailey V5 The Scout EOS four stroke looks to be (fundamentally) a Bailey V5 with what looks to be a very useful power increase but I will guarantee it will be too pricy for a skinflint like me! Quote Link to comment Share on other sites More sharing options...
Blackburn Mark Posted September 19, 2020 Share Posted September 19, 2020 4 hours ago, Hann__ said: Yep, that`s excellent alright, i don`t think many 2T`s would be able to get near that! Looking at your water hopping flight, you must have quite a fuel capacity on that thing! Quote Link to comment Share on other sites More sharing options...
Hann__ Posted September 19, 2020 Share Posted September 19, 2020 6 minutes ago, Blackburn Mark said: Looking at your water hopping flight, you must have quite a fuel capacity on that thing! I get 3.5l/hr on my Moster 185 and with a 15 litre tank can go over 4 hours. Quote Link to comment Share on other sites More sharing options...
chrsfrwll Posted September 19, 2020 Share Posted September 19, 2020 25 minutes ago, Blackburn Mark said: Last Monday, I flew to Malam cove with a guy who burned almost 15Llr in two hours... He only just made it back. Yikes, now that is one thirsty motor. Not seen a burn rate that high before. I would definitely be looking at alternatives. 25 minutes ago, Blackburn Mark said: The Scout EOS four stroke looks to be (fundamentally) a Bailey V5 with what looks to be a very useful power increase but I will guarantee it will be too pricy for a skinflint like me! That I think is a given. Edit - the too pricey bit, not you being a skinflint 1 Quote Link to comment Share on other sites More sharing options...
Blackburn Mark Posted September 19, 2020 Share Posted September 19, 2020 2 minutes ago, Hann__ said: I get 3.5l/hr on my Moster 185 and with a 15 litre tank can go over 4 hours. That has me thinking the guy I flew to Malam with must be running very rich! I think it was an early Air Conception machine... ill have to quiz him when I see him. Quote Link to comment Share on other sites More sharing options...
Blackburn Mark Posted September 19, 2020 Share Posted September 19, 2020 4 minutes ago, chrsfrwll said: Yikes, now that is one thirsty motor. Now I think about it, he said he had enough fuel to brim his motor so I might be wrongly assuming he did "brim it". Either that or at 7.5 lph he must have been trailing raw hydrocarbons all over the sky! Quote Link to comment Share on other sites More sharing options...
Bob27 Posted September 20, 2020 Share Posted September 20, 2020 (edited) On 18/09/2020 at 11:31, chrsfrwll said: I've got all of that from my Atom 80 running Aspen fuel, plus it weighs a lot less. But does your atom 80 have 27hp? Lol One big problem is that at lower loads the engines loose more efficiency(2 strokes are way worse in this aspect then 4 strokes). So a vittorazi engine while cruising is running at about 1/5 power and gets a calculated ~6% thermal efficiency. On the other hand your atom 80 is running at closer to 1/3 power cruising and thanks to this extra load gets roughly 8-9% thermal efficiency at said power. But at 90% throttle both engines are close to 10% efficient. The big idea is that 4 strokes don't loose efficiency at low loads as bad as 2 strokes so that you can have the power of a big engine with the cruising efficiency of a small engine. Edited September 20, 2020 by Bob27 1 Quote Link to comment Share on other sites More sharing options...
Paul White Posted October 29, 2022 Share Posted October 29, 2022 On 8/20/2017 at 8:04 PM, Casper said: So would an engine like the Moki 400cc 5 cylinder radial engine work? it's about 23hp and weight 9,2 kg. Since it have low rpm and high torque it should work as direct drive. Or even better, the VM R5-420, 5 cylinder from Valach that have 25hp and weighs just 11,8 kg (without exhaust, many options there). Recommended propeller diameter for RC are up to 106cm for the wooden propellers. I'm almost sure a nice lightweight carbon propeller with a slightly bigger diameter would fit. Biggest problem would be cooling as I see it, and maintance. Fuel economy is actually very good according to some websites (better than our 2strokes). Ofc it's not an optimal engine for ppg, but I would love to show up with radial engine on my back, and the sound is magic! I've sent a tentative enquiry to Valach. I too am curious about the 420cc radial. Probably not a workhorse but could be entertaining for little flights on a fine day. I'm just learning to fly. Not sure if the lack of clutch would be a dealbreaker. 250 shown below with enclosed valve train. Quote Link to comment Share on other sites More sharing options...
alan_k Posted October 29, 2022 Share Posted October 29, 2022 Ooh a radial for a paramotor, that would be novel. 25 hp is good, can the all up weight match a BaileyV5, about 28.5kg dry or less? Quote Link to comment Share on other sites More sharing options...
Paul White Posted November 14, 2022 Share Posted November 14, 2022 On 10/29/2022 at 5:20 PM, alan_k said: Ooh a radial for a paramotor, that would be novel. 25 hp is good, can the all up weight match a BaileyV5, about 28.5kg dry or less? They're about 12kg. A battery for the fuel pump/ignition/starter would increase the weight. Quote Link to comment Share on other sites More sharing options...
Paul White Posted December 9, 2022 Share Posted December 9, 2022 Does anyone know if you're free to install whatever engine you like in a paramotor in the UK? A four stroke model aircraft engine may be nice, but not if it renders you uninsured etc. Quote Link to comment Share on other sites More sharing options...
Blackburn Mark Posted December 9, 2022 Share Posted December 9, 2022 2 minutes ago, Paul White said: Does anyone know if you're free to install whatever engine you like in a paramotor in the UK? A four stroke model aircraft engine may be nice, but not if it renders you uninsured etc. As long as your entire kit weighs less than 75kg with a reserve, you are good. 1 Quote Link to comment Share on other sites More sharing options...
Paul White Posted December 9, 2022 Share Posted December 9, 2022 41 minutes ago, Blackburn Mark said: As long as your entire kit weighs less than 75kg with a reserve, you are good. Thank you Mark. That's very helpful Quote Link to comment Share on other sites More sharing options...
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