Spin vs ONI system
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Spin
Calculate critical aviation weather data including wind components, temperature conversions, altitude calculations, and airspeed. Designed for pilots with an intuitive, one-handed interface and instant results.
- Wind component calculation (headwind, tailwind, crosswind)
- Temperature conversions and wind chill factor
- Altitude calculations (pressure, density)
- Airspeed calculator (TAS, Mach, speed of sound)
- Customizable units and caution thresholds
- One-handed, reel-based interface
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Featured in Flying Magazine July 2012 "8 Great Aviation Apps"! Reviewed favorably on AOPA Flight Planning App Roulette 20 Nov 2012 Designed by an airline pilot, Spin-a-Wind calculates wind components, temperatures, altitudes and airspeeds. The headwind (tailwind) and crosswind components are based on the runway, and reported wind direction and speed. If the airport has parallel runways, using the runway number closest to the actual magnetic heading of the runway gives the most accurate results. The result is also displayed graphically. Crosswind and tailwind components are rounded up, while the headwind component is rounded down, making sure that all results depict the worst case. To instantly change to the opposite (reciprocal) runway, tap the runway number at the far end. Spinning reels are used to make your selections. No keyboard is necessary. Results of calculations are displayed instantly when the last reel stops. The app was designed for one handed use, and ease of operation. The second item on the tab bar links you to a page with temperature conversions. Enter the temperature in degrees Celsius, and instantly the Fahrenheit conversion is displayed, as well as the chill factor in °C and °F using the NWS Wind Chill index used by the U.S. and Canada. (note: the NWS Wind Chill index is not valid for greater than 50°F or less than 3 mph of wind. Relative Humidity and Heat Stress Index are calculated using the entered Dewpoint Temperature. The third item deals with altitudes, metric, pressure altitude and density altitude. Density altitude is diaplayed for assumed dry air, and also moist air (based upon the temp/dewpoint spread entered in the temperature page. The fourth item is the Airspeed Calculator. It uses equations for TAS, mach, and speed of sound. The equations used will be accurate even for the higher speeds of jet aircraft. The fifth item on the tab bar moves the view to the settings page. Here, you can set your display speed units (kts, mph, kph) and pressure units(inHg, hPa, mb) as well as the threshold points where the wind results turn amber (caution zone) and red (aircraft limits).
ONI system
Access and view crucial asset data, including lists, real-time positions, and traffic information. Track trips, view routes, and get detailed asset states like temperature and battery levels. Navigate directly to asset locations.
- View asset lists
- Real-time asset positions
- Google traffic near assets
- Logbook of trips
- Asset route history
- Navigation to asset location
- Detailed asset states
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The ONI system app displays the most important assets data. After login in the ONI system you gain access to view: - lists of assets, - actual assets positions, - Google traffic near the asset, - list of trips (logbook), - routes driven by the asset, - navigation to the actual asset's position, - detailed states of the asset (e.g. temperature, battery charge level, trip type etc.).
Screenshots
Verdict
The clearest difference is review sentiment: Spin at 86% against ONI system's 33%. Spin also leads on iOS requirement (6.0 vs 13.0). ONI system's advantage is price (Free vs $2.99) and update cadence (every 6 weeks vs every 3 months). On ads, in-app purchases and device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
ONI system is free to download; Spin costs $2.99 up front. Neither carries in-app purchases, so what you see is what you pay.
Spin ships an update every 3 months, ONI system every 6 weeks. The most recent releases landed on September 25, 2026 and September 14, 2026 respectively.
| Parameter | Spin | ONI system |
|---|---|---|
| Price | $2.99 | Free — better |
| Rating | 4.6 (44 ratings) — better | — |
| Positive reviews | 86.1% of reviews — better | 33.3% of reviews |
| Number of ratings | 44 — better | — |
| Update frequency | Every 3 months | Every 6 weeks — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Paid | Free — better |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 6.0 — better | 13.0 |
| Further details — not scored | ||
| Size | 10 MB | 90 MB |
| Age rating | 4+ | 4+ |
| Developer | Len Robinson | NAM system a.s. |
Customer experience
Spin
ONI system
In-app purchases
Spin
No in-app purchases
ONI system
No in-app purchases









